SDL/include/SDL3/SDL_stdinc.h

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2024 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/

/**
 * # CategoryStdinc
 *
 * This is a general header that includes C language support. It implements a
 * subset of the C runtime APIs, but with an `SDL_` prefix. For most common
 * use cases, these should behave the same way as their C runtime equivalents,
 * but they may differ in how or whether they handle certain edge cases. When
 * in doubt, consult the documentation for details.
 */

#ifndef SDL_stdinc_h_
#define SDL_stdinc_h_

#include <SDL3/SDL_platform_defines.h>

#include <stdarg.h>
#include <stdint.h>
#include <string.h>
#include <wchar.h>

#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) || \
    defined(SDL_INCLUDE_INTTYPES_H)
#include <inttypes.h>
#endif

#ifndef __cplusplus
#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) || \
    (defined(_MSC_VER) && (_MSC_VER >= 1910 /* Visual Studio 2017 */)) || \
    defined(SDL_INCLUDE_STDBOOL_H)
#include <stdbool.h>
#elif !defined(__bool_true_false_are_defined) && !defined(bool)
#define bool  unsigned char
#define false 0
#define true  1
#define __bool_true_false_are_defined 1
#endif
#endif /* !__cplusplus */

#ifndef SDL_DISABLE_ALLOCA
# ifndef alloca
#  ifdef HAVE_ALLOCA_H
#   include <alloca.h>
#  elif defined(SDL_PLATFORM_NETBSD)
#   if defined(__STRICT_ANSI__)
#    define SDL_DISABLE_ALLOCA
#   else
#    include <stdlib.h>
#   endif
#  elif defined(__GNUC__)
#   define alloca __builtin_alloca
#  elif defined(_MSC_VER)
#   include <malloc.h>
#   define alloca _alloca
#  elif defined(__WATCOMC__)
#   include <malloc.h>
#  elif defined(__BORLANDC__)
#   include <malloc.h>
#  elif defined(__DMC__)
#   include <stdlib.h>
#  elif defined(SDL_PLATFORM_AIX)
# pragma alloca
#  elif defined(__MRC__)
void *alloca(unsigned);
#  else
void *alloca(size_t);
#  endif
# endif
#endif

#ifdef SDL_WIKI_DOCUMENTATION_SECTION

/**
 * The largest value that a `size_t` can hold for the target platform.
 *
 * `size_t` is generally the same size as a pointer in modern times, but this
 * can get weird on very old and very esoteric machines. For example, on a
 * 16-bit Intel 286, you might have a 32-bit "far" pointer (16-bit segment
 * plus 16-bit offset), but `size_t` is 16 bits, because it can only deal with
 * the offset into an individual segment.
 *
 * In modern times, it's generally expected to cover an entire linear address
 * space. But be careful!
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_SIZE_MAX SIZE_MAX

#elif defined(SIZE_MAX)
# define SDL_SIZE_MAX SIZE_MAX
#else
# define SDL_SIZE_MAX ((size_t) -1)
#endif

#ifndef SDL_COMPILE_TIME_ASSERT
#ifdef SDL_WIKI_DOCUMENTATION_SECTION

/**
 * A compile-time assertion.
 *
 * This can check constant values _known to the compiler at build time_ for
 * correctness, and end the compile with the error if they fail.
 *
 * Often times these are used to verify basic truths, like the size of a
 * datatype is what is expected:
 *
 * ```c
 * SDL_COMPILE_TIME_ASSERT(uint32_size, sizeof(Uint32) == 4);
 * ```
 *
 * The `name` parameter must be a valid C symbol, and must be unique across
 * all compile-time asserts in the same compilation unit (one run of the
 * compiler), or the build might fail with cryptic errors on some targets.
 * This is used with a C language trick that works on older compilers that
 * don't support better assertion techniques.
 *
 * If you need an assertion that operates at runtime, on variable data, you
 * should try SDL_assert instead.
 *
 * \param name a unique identifier for this assertion.
 * \param x the value to test. Must be a boolean value.
 *
 * \threadsafety This macro doesn't generate any code to run.
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_assert
 */
#define SDL_COMPILE_TIME_ASSERT(name, x) FailToCompileIf_x_IsFalse(x)
#elif defined(__cplusplus)
/* Keep C++ case alone: Some versions of gcc will define __STDC_VERSION__ even when compiling in C++ mode. */
#if (__cplusplus >= 201103L)
#define SDL_COMPILE_TIME_ASSERT(name, x)  static_assert(x, #x)
#endif
#elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 202311L)
#define SDL_COMPILE_TIME_ASSERT(name, x)  static_assert(x, #x)
#elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L)
#define SDL_COMPILE_TIME_ASSERT(name, x) _Static_assert(x, #x)
#endif
#endif /* !SDL_COMPILE_TIME_ASSERT */

#ifndef SDL_COMPILE_TIME_ASSERT
/* universal, but may trigger -Wunused-local-typedefs */
#define SDL_COMPILE_TIME_ASSERT(name, x)               \
       typedef int SDL_compile_time_assert_ ## name[(x) * 2 - 1]
#endif

/**
 * The number of elements in a static array.
 *
 * This will compile but return incorrect results for a pointer to an array;
 * it has to be an array the compiler knows the size of.
 *
 * This macro looks like it double-evaluates the argument, but it does so
 * inside of `sizeof`, so there are no side-effects here, as expressions do
 * not actually run any code in these cases.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_arraysize(array) (sizeof(array)/sizeof(array[0]))

/**
 * Macro useful for building other macros with strings in them.
 *
 * For example:
 *
 * ```c
 * #define LOG_ERROR(X) OutputDebugString(SDL_STRINGIFY_ARG(__FUNCTION__) ": " X "\n")`
 * ```
 *
 * \param arg the text to turn into a string literal.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_STRINGIFY_ARG(arg)  #arg

/**
 *  \name Cast operators
 *
 *  Use proper C++ casts when compiled as C++ to be compatible with the option
 *  -Wold-style-cast of GCC (and -Werror=old-style-cast in GCC 4.2 and above).
 */
/* @{ */

#ifdef SDL_WIKI_DOCUMENTATION_SECTION

/**
 * Handle a Reinterpret Cast properly whether using C or C++.
 *
 * If compiled as C++, this macro offers a proper C++ reinterpret_cast<>.
 *
 * If compiled as C, this macro does a normal C-style cast.
 *
 * This is helpful to avoid compiler warnings in C++.
 *
 * \param type the type to cast the expression to.
 * \param expression the expression to cast to a different type.
 * \returns `expression`, cast to `type`.
 *
 * \threadsafety It is safe to call this macro from any thread.
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_static_cast
 * \sa SDL_const_cast
 */
#define SDL_reinterpret_cast(type, expression) reinterpret_cast<type>(expression)  /* or `((type)(expression))` in C */

/**
 * Handle a Static Cast properly whether using C or C++.
 *
 * If compiled as C++, this macro offers a proper C++ static_cast<>.
 *
 * If compiled as C, this macro does a normal C-style cast.
 *
 * This is helpful to avoid compiler warnings in C++.
 *
 * \param type the type to cast the expression to.
 * \param expression the expression to cast to a different type.
 * \returns `expression`, cast to `type`.
 *
 * \threadsafety It is safe to call this macro from any thread.
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_reinterpret_cast
 * \sa SDL_const_cast
 */
#define SDL_static_cast(type, expression) static_cast<type>(expression)  /* or `((type)(expression))` in C */

/**
 * Handle a Const Cast properly whether using C or C++.
 *
 * If compiled as C++, this macro offers a proper C++ const_cast<>.
 *
 * If compiled as C, this macro does a normal C-style cast.
 *
 * This is helpful to avoid compiler warnings in C++.
 *
 * \param type the type to cast the expression to.
 * \param expression the expression to cast to a different type.
 * \returns `expression`, cast to `type`.
 *
 * \threadsafety It is safe to call this macro from any thread.
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_reinterpret_cast
 * \sa SDL_static_cast
 */
#define SDL_const_cast(type, expression) const_cast<type>(expression)  /* or `((type)(expression))` in C */

#elif defined(__cplusplus)
#define SDL_reinterpret_cast(type, expression) reinterpret_cast<type>(expression)
#define SDL_static_cast(type, expression) static_cast<type>(expression)
#define SDL_const_cast(type, expression) const_cast<type>(expression)
#else
#define SDL_reinterpret_cast(type, expression) ((type)(expression))
#define SDL_static_cast(type, expression) ((type)(expression))
#define SDL_const_cast(type, expression) ((type)(expression))
#endif

/* @} *//* Cast operators */

/**
 * Define a four character code as a Uint32.
 *
 * \param A the first ASCII character.
 * \param B the second ASCII character.
 * \param C the third ASCII character.
 * \param D the fourth ASCII character.
 * \returns the four characters converted into a Uint32, one character
 *          per-byte.
 *
 * \threadsafety It is safe to call this macro from any thread.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_FOURCC(A, B, C, D) \
    ((SDL_static_cast(Uint32, SDL_static_cast(Uint8, (A))) << 0) | \
     (SDL_static_cast(Uint32, SDL_static_cast(Uint8, (B))) << 8) | \
     (SDL_static_cast(Uint32, SDL_static_cast(Uint8, (C))) << 16) | \
     (SDL_static_cast(Uint32, SDL_static_cast(Uint8, (D))) << 24))

#ifdef SDL_WIKI_DOCUMENTATION_SECTION

/**
 * Append the 64 bit integer suffix to a signed integer literal.
 *
 * This helps compilers that might believe a integer literal larger than
 * 0xFFFFFFFF is overflowing a 32-bit value. Use `SDL_SINT64_C(0xFFFFFFFF1)`
 * instead of `0xFFFFFFFF1` by itself.
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_UINT64_C
 */
#define SDL_SINT64_C(c)  c ## LL  /* or whatever the current compiler uses. */

/**
 * Append the 64 bit integer suffix to an unsigned integer literal.
 *
 * This helps compilers that might believe a integer literal larger than
 * 0xFFFFFFFF is overflowing a 32-bit value. Use `SDL_UINT64_C(0xFFFFFFFF1)`
 * instead of `0xFFFFFFFF1` by itself.
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_SINT64_C
 */
#define SDL_UINT64_C(c)  c ## ULL /* or whatever the current compiler uses. */

#else /* !SDL_WIKI_DOCUMENTATION_SECTION */

#ifndef SDL_SINT64_C
#if defined(INT64_C)
#define SDL_SINT64_C(c)  INT64_C(c)
#elif defined(_MSC_VER)
#define SDL_SINT64_C(c)  c ## i64
#elif defined(__LP64__) || defined(_LP64)
#define SDL_SINT64_C(c)  c ## L
#else
#define SDL_SINT64_C(c)  c ## LL
#endif
#endif /* !SDL_SINT64_C */

#ifndef SDL_UINT64_C
#if defined(UINT64_C)
#define SDL_UINT64_C(c)  UINT64_C(c)
#elif defined(_MSC_VER)
#define SDL_UINT64_C(c)  c ## ui64
#elif defined(__LP64__) || defined(_LP64)
#define SDL_UINT64_C(c)  c ## UL
#else
#define SDL_UINT64_C(c)  c ## ULL
#endif
#endif /* !SDL_UINT64_C */

#endif /* !SDL_WIKI_DOCUMENTATION_SECTION */

/**
 *  \name Basic data types
 */
/* @{ */

/**
 * A signed 8-bit integer type.
 *
 * \since This macro is available since SDL 3.1.3.
 */
typedef int8_t Sint8;
#define SDL_MAX_SINT8   ((Sint8)0x7F)           /* 127 */
#define SDL_MIN_SINT8   ((Sint8)(~0x7F))        /* -128 */

/**
 * An unsigned 8-bit integer type.
 *
 * \since This macro is available since SDL 3.1.3.
 */
typedef uint8_t Uint8;
#define SDL_MAX_UINT8   ((Uint8)0xFF)           /* 255 */
#define SDL_MIN_UINT8   ((Uint8)0x00)           /* 0 */

/**
 * A signed 16-bit integer type.
 *
 * \since This macro is available since SDL 3.1.3.
 */
typedef int16_t Sint16;
#define SDL_MAX_SINT16  ((Sint16)0x7FFF)        /* 32767 */
#define SDL_MIN_SINT16  ((Sint16)(~0x7FFF))     /* -32768 */

/**
 * An unsigned 16-bit integer type.
 *
 * \since This macro is available since SDL 3.1.3.
 */
typedef uint16_t Uint16;
#define SDL_MAX_UINT16  ((Uint16)0xFFFF)        /* 65535 */
#define SDL_MIN_UINT16  ((Uint16)0x0000)        /* 0 */

/**
 * A signed 32-bit integer type.
 *
 * \since This macro is available since SDL 3.1.3.
 */
typedef int32_t Sint32;
#define SDL_MAX_SINT32  ((Sint32)0x7FFFFFFF)    /* 2147483647 */
#define SDL_MIN_SINT32  ((Sint32)(~0x7FFFFFFF)) /* -2147483648 */

/**
 * An unsigned 32-bit integer type.
 *
 * \since This macro is available since SDL 3.1.3.
 */
typedef uint32_t Uint32;
#define SDL_MAX_UINT32  ((Uint32)0xFFFFFFFFu)   /* 4294967295 */
#define SDL_MIN_UINT32  ((Uint32)0x00000000)    /* 0 */

/**
 * A signed 64-bit integer type.
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_SINT64_C
 */
typedef int64_t Sint64;
#define SDL_MAX_SINT64  SDL_SINT64_C(0x7FFFFFFFFFFFFFFF)   /* 9223372036854775807 */
#define SDL_MIN_SINT64  ~SDL_SINT64_C(0x7FFFFFFFFFFFFFFF)  /* -9223372036854775808 */

/**
 * An unsigned 64-bit integer type.
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_UINT64_C
 */
typedef uint64_t Uint64;
#define SDL_MAX_UINT64  SDL_UINT64_C(0xFFFFFFFFFFFFFFFF)   /* 18446744073709551615 */
#define SDL_MIN_UINT64  SDL_UINT64_C(0x0000000000000000)   /* 0 */

/**
 * SDL times are signed, 64-bit integers representing nanoseconds since the
 * Unix epoch (Jan 1, 1970).
 *
 * They can be converted between POSIX time_t values with SDL_NS_TO_SECONDS()
 * and SDL_SECONDS_TO_NS(), and between Windows FILETIME values with
 * SDL_TimeToWindows() and SDL_TimeFromWindows().
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_MAX_SINT64
 * \sa SDL_MIN_SINT64
 */
typedef Sint64 SDL_Time;
#define SDL_MAX_TIME SDL_MAX_SINT64
#define SDL_MIN_TIME SDL_MIN_SINT64

/* @} *//* Basic data types */

/**
 *  \name Floating-point constants
 */
/* @{ */

#ifdef FLT_EPSILON
#define SDL_FLT_EPSILON FLT_EPSILON
#else

/**
 * Epsilon constant, used for comparing floating-point numbers.
 *
 * Equals by default to platform-defined `FLT_EPSILON`, or
 * `1.1920928955078125e-07F` if that's not available.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_FLT_EPSILON 1.1920928955078125e-07F /* 0x0.000002p0 */
#endif

/* @} *//* Floating-point constants */

#ifdef SDL_WIKI_DOCUMENTATION_SECTION

/**
 * A printf-formatting string for an Sint64 value.
 *
 * Use it like this:
 *
 * ```c
 * SDL_Log("There are %" SDL_PRIs64 " bottles of beer on the wall.", bottles);
 * ```
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_PRIs64 "lld"

/**
 * A printf-formatting string for a Uint64 value.
 *
 * Use it like this:
 *
 * ```c
 * SDL_Log("There are %" SDL_PRIu64 " bottles of beer on the wall.", bottles);
 * ```
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_PRIu64 "llu"

/**
 * A printf-formatting string for a Uint64 value as lower-case hexadecimal.
 *
 * Use it like this:
 *
 * ```c
 * SDL_Log("There are %" SDL_PRIx64 " bottles of beer on the wall.", bottles);
 * ```
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_PRIx64 "llx"

/**
 * A printf-formatting string for a Uint64 value as upper-case hexadecimal.
 *
 * Use it like this:
 *
 * ```c
 * SDL_Log("There are %" SDL_PRIX64 " bottles of beer on the wall.", bottles);
 * ```
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_PRIX64 "llX"

/**
 * A printf-formatting string for an Sint32 value.
 *
 * Use it like this:
 *
 * ```c
 * SDL_Log("There are %" SDL_PRIs32 " bottles of beer on the wall.", bottles);
 * ```
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_PRIs32 "d"

/**
 * A printf-formatting string for a Uint32 value.
 *
 * Use it like this:
 *
 * ```c
 * SDL_Log("There are %" SDL_PRIu32 " bottles of beer on the wall.", bottles);
 * ```
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_PRIu32 "u"

/**
 * A printf-formatting string for a Uint32 value as lower-case hexadecimal.
 *
 * Use it like this:
 *
 * ```c
 * SDL_Log("There are %" SDL_PRIx32 " bottles of beer on the wall.", bottles);
 * ```
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_PRIx32 "x"

/**
 * A printf-formatting string for a Uint32 value as upper-case hexadecimal.
 *
 * Use it like this:
 *
 * ```c
 * SDL_Log("There are %" SDL_PRIX32 " bottles of beer on the wall.", bottles);
 * ```
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_PRIX32 "X"

/**
 * A printf-formatting string prefix for a `long long` value.
 *
 * This is just the prefix! You probably actually want SDL_PRILLd, SDL_PRILLu,
 * SDL_PRILLx, or SDL_PRILLX instead.
 *
 * Use it like this:
 *
 * ```c
 * SDL_Log("There are %" SDL_PRILL_PREFIX "d bottles of beer on the wall.", bottles);
 * ```
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_PRILL_PREFIX "ll"

/**
 * A printf-formatting string for a `long long` value.
 *
 * Use it like this:
 *
 * ```c
 * SDL_Log("There are %" SDL_PRILLd " bottles of beer on the wall.", bottles);
 * ```
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_PRILLd SDL_PRILL_PREFIX "d"

/**
 * A printf-formatting string for a `unsigned long long` value.
 *
 * Use it like this:
 *
 * ```c
 * SDL_Log("There are %" SDL_PRILLu " bottles of beer on the wall.", bottles);
 * ```
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_PRILLu SDL_PRILL_PREFIX "u"

/**
 * A printf-formatting string for an `unsigned long long` value as lower-case
 * hexadecimal.
 *
 * Use it like this:
 *
 * ```c
 * SDL_Log("There are %" SDL_PRILLx " bottles of beer on the wall.", bottles);
 * ```
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_PRILLx SDL_PRILL_PREFIX "x"

/**
 * A printf-formatting string for an `unsigned long long` value as upper-case
 * hexadecimal.
 *
 * Use it like this:
 *
 * ```c
 * SDL_Log("There are %" SDL_PRILLX " bottles of beer on the wall.", bottles);
 * ```
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_PRILLX SDL_PRILL_PREFIX "X"
#endif /* SDL_WIKI_DOCUMENTATION_SECTION */

/* Make sure we have macros for printing width-based integers.
 * <inttypes.h> should define these but this is not true all platforms.
 * (for example win32) */
#ifndef SDL_PRIs64
#if defined(SDL_PLATFORM_WINDOWS)
#define SDL_PRIs64 "I64d"
#elif defined(PRId64)
#define SDL_PRIs64 PRId64
#elif defined(__LP64__) && !defined(SDL_PLATFORM_APPLE) && !defined(__EMSCRIPTEN__)
#define SDL_PRIs64 "ld"
#else
#define SDL_PRIs64 "lld"
#endif
#endif
#ifndef SDL_PRIu64
#if defined(SDL_PLATFORM_WINDOWS)
#define SDL_PRIu64 "I64u"
#elif defined(PRIu64)
#define SDL_PRIu64 PRIu64
#elif defined(__LP64__) && !defined(SDL_PLATFORM_APPLE) && !defined(__EMSCRIPTEN__)
#define SDL_PRIu64 "lu"
#else
#define SDL_PRIu64 "llu"
#endif
#endif
#ifndef SDL_PRIx64
#if defined(SDL_PLATFORM_WINDOWS)
#define SDL_PRIx64 "I64x"
#elif defined(PRIx64)
#define SDL_PRIx64 PRIx64
#elif defined(__LP64__) && !defined(SDL_PLATFORM_APPLE)
#define SDL_PRIx64 "lx"
#else
#define SDL_PRIx64 "llx"
#endif
#endif
#ifndef SDL_PRIX64
#if defined(SDL_PLATFORM_WINDOWS)
#define SDL_PRIX64 "I64X"
#elif defined(PRIX64)
#define SDL_PRIX64 PRIX64
#elif defined(__LP64__) && !defined(SDL_PLATFORM_APPLE)
#define SDL_PRIX64 "lX"
#else
#define SDL_PRIX64 "llX"
#endif
#endif
#ifndef SDL_PRIs32
#ifdef PRId32
#define SDL_PRIs32 PRId32
#else
#define SDL_PRIs32 "d"
#endif
#endif
#ifndef SDL_PRIu32
#ifdef PRIu32
#define SDL_PRIu32 PRIu32
#else
#define SDL_PRIu32 "u"
#endif
#endif
#ifndef SDL_PRIx32
#ifdef PRIx32
#define SDL_PRIx32 PRIx32
#else
#define SDL_PRIx32 "x"
#endif
#endif
#ifndef SDL_PRIX32
#ifdef PRIX32
#define SDL_PRIX32 PRIX32
#else
#define SDL_PRIX32 "X"
#endif
#endif
/* Specifically for the `long long` -- SDL-specific. */
#ifdef SDL_PLATFORM_WINDOWS
SDL_COMPILE_TIME_ASSERT(longlong_size64, sizeof(long long) == 8); /* using I64 for windows - make sure `long long` is 64 bits. */
#define SDL_PRILL_PREFIX "I64"
#else
#define SDL_PRILL_PREFIX "ll"
#endif
#ifndef SDL_PRILLd
#define SDL_PRILLd SDL_PRILL_PREFIX "d"
#endif
#ifndef SDL_PRILLu
#define SDL_PRILLu SDL_PRILL_PREFIX "u"
#endif
#ifndef SDL_PRILLx
#define SDL_PRILLx SDL_PRILL_PREFIX "x"
#endif
#ifndef SDL_PRILLX
#define SDL_PRILLX SDL_PRILL_PREFIX "X"
#endif

/* Annotations to help code analysis tools */
#ifdef SDL_WIKI_DOCUMENTATION_SECTION

/**
 * Macro that annotates function params with input buffer size.
 *
 * If we were to annotate `memcpy`:
 *
 * ```c
 * void *memcpy(void *dst, SDL_IN_BYTECAP(len) const void *src, size_t len);
 * ```
 *
 * This notes that `src` should be `len` bytes in size and is only read by the
 * function. The compiler or other analysis tools can warn when this doesn't
 * appear to be the case.
 *
 * On compilers without this annotation mechanism, this is defined to nothing.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_IN_BYTECAP(x) _In_bytecount_(x)

/**
 * Macro that annotates function params with input/output string buffer size.
 *
 * If we were to annotate `strlcat`:
 *
 * ```c
 * size_t strlcat(SDL_INOUT_Z_CAP(maxlen) char *dst, const char *src, size_t maxlen);
 * ```
 *
 * This notes that `dst` is a null-terminated C string, should be `maxlen`
 * bytes in size, and is both read from and written to by the function. The
 * compiler or other analysis tools can warn when this doesn't appear to be
 * the case.
 *
 * On compilers without this annotation mechanism, this is defined to nothing.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_INOUT_Z_CAP(x) _Inout_z_cap_(x)

/**
 * Macro that annotates function params with output string buffer size.
 *
 * If we were to annotate `snprintf`:
 *
 * ```c
 * int snprintf(SDL_OUT_Z_CAP(maxlen) char *text, size_t maxlen, const char *fmt, ...);
 * ```
 *
 * This notes that `text` is a null-terminated C string, should be `maxlen`
 * bytes in size, and is only written to by the function. The compiler or
 * other analysis tools can warn when this doesn't appear to be the case.
 *
 * On compilers without this annotation mechanism, this is defined to nothing.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_OUT_Z_CAP(x) _Out_z_cap_(x)

/**
 * Macro that annotates function params with output buffer size.
 *
 * If we were to annotate `wcsncpy`:
 *
 * ```c
 * char *wcscpy(SDL_OUT_CAP(bufsize) wchar_t *dst, const wchar_t *src, size_t bufsize);
 * ```
 *
 * This notes that `dst` should have a capacity of `bufsize` wchar_t in size,
 * and is only written to by the function. The compiler or other analysis
 * tools can warn when this doesn't appear to be the case.
 *
 * This operates on counts of objects, not bytes. Use SDL_OUT_BYTECAP for bytes.
 *
 * On compilers without this annotation mechanism, this is defined to nothing.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_OUT_CAP(x) _Out_cap_(x)

/**
 * Macro that annotates function params with output buffer size.
 *
 * If we were to annotate `memcpy`:
 *
 * ```c
 * void *memcpy(SDL_OUT_BYTECAP(bufsize) void *dst, const void *src, size_t bufsize);
 * ```
 *
 * This notes that `dst` should have a capacity of `bufsize` bytes in size,
 * and is only written to by the function. The compiler or other analysis
 * tools can warn when this doesn't appear to be the case.
 *
 * On compilers without this annotation mechanism, this is defined to nothing.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_OUT_BYTECAP(x) _Out_bytecap_(x)

/**
 * Macro that annotates function params with output buffer string size.
 *
 * If we were to annotate `strcpy`:
 *
 * ```c
 * char *strcpy(SDL_OUT_Z_BYTECAP(bufsize) char *dst, const char *src, size_t bufsize);
 * ```
 *
 * This notes that `dst` should have a capacity of `bufsize` bytes in size,
 * and a zero-terminated string is written to it by the function. The compiler
 * or other analysis tools can warn when this doesn't appear to be the case.
 *
 * On compilers without this annotation mechanism, this is defined to nothing.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_OUT_Z_BYTECAP(x) _Out_z_bytecap_(x)

/**
 * Macro that annotates function params as printf-style format strings.
 *
 * If we were to annotate `fprintf`:
 *
 * ```c
 * int fprintf(FILE *f, SDL_PRINTF_FORMAT_STRING const char *fmt, ...);
 * ```
 *
 * This notes that `fmt` should be a printf-style format string. The compiler
 * or other analysis tools can warn when this doesn't appear to be the case.
 *
 * On compilers without this annotation mechanism, this is defined to nothing.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_PRINTF_FORMAT_STRING _Printf_format_string_

/**
 * Macro that annotates function params as scanf-style format strings.
 *
 * If we were to annotate `fscanf`:
 *
 * ```c
 * int fscanf(FILE *f, SDL_SCANF_FORMAT_STRING const char *fmt, ...);
 * ```
 *
 * This notes that `fmt` should be a scanf-style format string. The compiler
 * or other analysis tools can warn when this doesn't appear to be the case.
 *
 * On compilers without this annotation mechanism, this is defined to nothing.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_SCANF_FORMAT_STRING _Scanf_format_string_impl_

/**
 * Macro that annotates a vararg function that operates like printf.
 *
 * If we were to annotate `fprintf`:
 *
 * ```c
 * int fprintf(FILE *f, const char *fmt, ...) SDL_PRINTF_VARARG_FUNC(2);
 * ```
 *
 * This notes that the second parameter should be a printf-style format string, followed by `...`.
 * The compiler or other analysis tools can warn when this doesn't appear to be the case.
 *
 * On compilers without this annotation mechanism, this is defined to nothing.
 *
 * This can (and should) be used with SDL_PRINTF_FORMAT_STRING as well, which between them
 * will cover at least Visual Studio, GCC, and Clang.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_PRINTF_VARARG_FUNC( fmtargnumber ) __attribute__ (( format( __printf__, fmtargnumber, fmtargnumber+1 )))

/**
 * Macro that annotates a va_list function that operates like printf.
 *
 * If we were to annotate `vfprintf`:
 *
 * ```c
 * int vfprintf(FILE *f, const char *fmt, va_list ap) SDL_PRINTF_VARARG_FUNCV(2);
 * ```
 *
 * This notes that the second parameter should be a printf-style format string, followed by a va_list.
 * The compiler or other analysis tools can warn when this doesn't appear to be the case.
 *
 * On compilers without this annotation mechanism, this is defined to nothing.
 *
 * This can (and should) be used with SDL_PRINTF_FORMAT_STRING as well, which between them
 * will cover at least Visual Studio, GCC, and Clang.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_PRINTF_VARARG_FUNCV( fmtargnumber ) __attribute__(( format( __printf__, fmtargnumber, 0 )))

/**
 * Macro that annotates a vararg function that operates like scanf.
 *
 * If we were to annotate `fscanf`:
 *
 * ```c
 * int fscanf(FILE *f, const char *fmt, ...) SDL_PRINTF_VARARG_FUNCV(2);
 * ```
 *
 * This notes that the second parameter should be a scanf-style format string, followed by `...`.
 * The compiler or other analysis tools can warn when this doesn't appear to be the case.
 *
 * On compilers without this annotation mechanism, this is defined to nothing.
 *
 * This can (and should) be used with SDL_SCANF_FORMAT_STRING as well, which between them
 * will cover at least Visual Studio, GCC, and Clang.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_SCANF_VARARG_FUNC( fmtargnumber ) __attribute__ (( format( __scanf__, fmtargnumber, fmtargnumber+1 )))

/**
 * Macro that annotates a va_list function that operates like scanf.
 *
 * If we were to annotate `vfscanf`:
 *
 * ```c
 * int vfscanf(FILE *f, const char *fmt, va_list ap) SDL_PRINTF_VARARG_FUNCV(2);
 * ```
 *
 * This notes that the second parameter should be a scanf-style format string, followed by a va_list.
 * The compiler or other analysis tools can warn when this doesn't appear to be the case.
 *
 * On compilers without this annotation mechanism, this is defined to nothing.
 *
 * This can (and should) be used with SDL_SCANF_FORMAT_STRING as well, which between them
 * will cover at least Visual Studio, GCC, and Clang.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_SCANF_VARARG_FUNCV( fmtargnumber ) __attribute__(( format( __scanf__, fmtargnumber, 0 )))

/**
 * Macro that annotates a vararg function that operates like wprintf.
 *
 * If we were to annotate `fwprintf`:
 *
 * ```c
 * int fwprintf(FILE *f, const wchar_t *fmt, ...) SDL_WPRINTF_VARARG_FUNC(2);
 * ```
 *
 * This notes that the second parameter should be a wprintf-style format wide string, followed by `...`.
 * The compiler or other analysis tools can warn when this doesn't appear to be the case.
 *
 * On compilers without this annotation mechanism, this is defined to nothing.
 *
 * This can (and should) be used with SDL_PRINTF_FORMAT_STRING as well, which between them
 * will cover at least Visual Studio, GCC, and Clang.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_WPRINTF_VARARG_FUNC( fmtargnumber ) /* __attribute__ (( format( __wprintf__, fmtargnumber, fmtargnumber+1 ))) */

/**
 * Macro that annotates a va_list function that operates like wprintf.
 *
 * If we were to annotate `vfwprintf`:
 *
 * ```c
 * int vfwprintf(FILE *f, const wchar_t *fmt, va_list ap) SDL_WPRINTF_VARARG_FUNC(2);
 * ```
 *
 * This notes that the second parameter should be a wprintf-style format wide string, followed by a va_list.
 * The compiler or other analysis tools can warn when this doesn't appear to be the case.
 *
 * On compilers without this annotation mechanism, this is defined to nothing.
 *
 * This can (and should) be used with SDL_PRINTF_FORMAT_STRING as well, which between them
 * will cover at least Visual Studio, GCC, and Clang.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_WPRINTF_VARARG_FUNCV( fmtargnumber ) /* __attribute__ (( format( __wprintf__, fmtargnumber, 0 ))) */

#elif defined(SDL_DISABLE_ANALYZE_MACROS)
#define SDL_IN_BYTECAP(x)
#define SDL_INOUT_Z_CAP(x)
#define SDL_OUT_Z_CAP(x)
#define SDL_OUT_CAP(x)
#define SDL_OUT_BYTECAP(x)
#define SDL_OUT_Z_BYTECAP(x)
#define SDL_PRINTF_FORMAT_STRING
#define SDL_SCANF_FORMAT_STRING
#define SDL_PRINTF_VARARG_FUNC( fmtargnumber )
#define SDL_PRINTF_VARARG_FUNCV( fmtargnumber )
#define SDL_SCANF_VARARG_FUNC( fmtargnumber )
#define SDL_SCANF_VARARG_FUNCV( fmtargnumber )
#define SDL_WPRINTF_VARARG_FUNC( fmtargnumber )
#define SDL_WPRINTF_VARARG_FUNCV( fmtargnumber )
#else
#if defined(_MSC_VER) && (_MSC_VER >= 1600) /* VS 2010 and above */
#include <sal.h>

#define SDL_IN_BYTECAP(x) _In_bytecount_(x)
#define SDL_INOUT_Z_CAP(x) _Inout_z_cap_(x)
#define SDL_OUT_Z_CAP(x) _Out_z_cap_(x)
#define SDL_OUT_CAP(x) _Out_cap_(x)
#define SDL_OUT_BYTECAP(x) _Out_bytecap_(x)
#define SDL_OUT_Z_BYTECAP(x) _Out_z_bytecap_(x)

#define SDL_PRINTF_FORMAT_STRING _Printf_format_string_
#define SDL_SCANF_FORMAT_STRING _Scanf_format_string_impl_
#else
#define SDL_IN_BYTECAP(x)
#define SDL_INOUT_Z_CAP(x)
#define SDL_OUT_Z_CAP(x)
#define SDL_OUT_CAP(x)
#define SDL_OUT_BYTECAP(x)
#define SDL_OUT_Z_BYTECAP(x)
#define SDL_PRINTF_FORMAT_STRING
#define SDL_SCANF_FORMAT_STRING
#endif
#if defined(__GNUC__) || defined(__clang__)
#define SDL_PRINTF_VARARG_FUNC( fmtargnumber ) __attribute__ (( format( __printf__, fmtargnumber, fmtargnumber+1 )))
#define SDL_PRINTF_VARARG_FUNCV( fmtargnumber ) __attribute__(( format( __printf__, fmtargnumber, 0 )))
#define SDL_SCANF_VARARG_FUNC( fmtargnumber ) __attribute__ (( format( __scanf__, fmtargnumber, fmtargnumber+1 )))
#define SDL_SCANF_VARARG_FUNCV( fmtargnumber ) __attribute__(( format( __scanf__, fmtargnumber, 0 )))
#define SDL_WPRINTF_VARARG_FUNC( fmtargnumber ) /* __attribute__ (( format( __wprintf__, fmtargnumber, fmtargnumber+1 ))) */
#define SDL_WPRINTF_VARARG_FUNCV( fmtargnumber ) /* __attribute__ (( format( __wprintf__, fmtargnumber, 0 ))) */
#else
#define SDL_PRINTF_VARARG_FUNC( fmtargnumber )
#define SDL_PRINTF_VARARG_FUNCV( fmtargnumber )
#define SDL_SCANF_VARARG_FUNC( fmtargnumber )
#define SDL_SCANF_VARARG_FUNCV( fmtargnumber )
#define SDL_WPRINTF_VARARG_FUNC( fmtargnumber )
#define SDL_WPRINTF_VARARG_FUNCV( fmtargnumber )
#endif
#endif /* SDL_DISABLE_ANALYZE_MACROS */

/** \cond */
#ifndef DOXYGEN_SHOULD_IGNORE_THIS
SDL_COMPILE_TIME_ASSERT(bool_size, sizeof(bool) == 1);
SDL_COMPILE_TIME_ASSERT(uint8_size, sizeof(Uint8) == 1);
SDL_COMPILE_TIME_ASSERT(sint8_size, sizeof(Sint8) == 1);
SDL_COMPILE_TIME_ASSERT(uint16_size, sizeof(Uint16) == 2);
SDL_COMPILE_TIME_ASSERT(sint16_size, sizeof(Sint16) == 2);
SDL_COMPILE_TIME_ASSERT(uint32_size, sizeof(Uint32) == 4);
SDL_COMPILE_TIME_ASSERT(sint32_size, sizeof(Sint32) == 4);
SDL_COMPILE_TIME_ASSERT(uint64_size, sizeof(Uint64) == 8);
SDL_COMPILE_TIME_ASSERT(sint64_size, sizeof(Sint64) == 8);
SDL_COMPILE_TIME_ASSERT(uint64_longlong, sizeof(Uint64) <= sizeof(unsigned long long));
SDL_COMPILE_TIME_ASSERT(size_t_longlong, sizeof(size_t) <= sizeof(unsigned long long));
typedef struct SDL_alignment_test
{
    Uint8 a;
    void *b;
} SDL_alignment_test;
SDL_COMPILE_TIME_ASSERT(struct_alignment, sizeof(SDL_alignment_test) == (2 * sizeof(void *)));
SDL_COMPILE_TIME_ASSERT(two_s_complement, (int)~(int)0 == (int)(-1));
#endif /* DOXYGEN_SHOULD_IGNORE_THIS */
/** \endcond */

/* Check to make sure enums are the size of ints, for structure packing.
   For both Watcom C/C++ and Borland C/C++ the compiler option that makes
   enums having the size of an int must be enabled.
   This is "-b" for Borland C/C++ and "-ei" for Watcom C/C++ (v11).
*/

/** \cond */
#ifndef DOXYGEN_SHOULD_IGNORE_THIS
#if !defined(SDL_PLATFORM_VITA) && !defined(SDL_PLATFORM_3DS)
/* TODO: include/SDL_stdinc.h:390: error: size of array 'SDL_dummy_enum' is negative */
typedef enum SDL_DUMMY_ENUM
{
    DUMMY_ENUM_VALUE
} SDL_DUMMY_ENUM;

SDL_COMPILE_TIME_ASSERT(enum, sizeof(SDL_DUMMY_ENUM) == sizeof(int));
#endif
#endif /* DOXYGEN_SHOULD_IGNORE_THIS */
/** \endcond */

#include <SDL3/SDL_begin_code.h>
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
extern "C" {
#endif

/**
 * A macro to initialize an SDL interface.
 *
 * This macro will initialize an SDL interface structure and should be called
 * before you fill out the fields with your implementation.
 *
 * You can use it like this:
 *
 * ```c
 * SDL_IOStreamInterface iface;
 *
 * SDL_INIT_INTERFACE(&iface);
 *
 * // Fill in the interface function pointers with your implementation
 * iface.seek = ...
 *
 * stream = SDL_OpenIO(&iface, NULL);
 * ```
 *
 * If you are using designated initializers, you can use the size of the
 * interface as the version, e.g.
 *
 * ```c
 * SDL_IOStreamInterface iface = {
 *     .version = sizeof(iface),
 *     .seek = ...
 * };
 * stream = SDL_OpenIO(&iface, NULL);
 * ```
 *
 * \threadsafety It is safe to call this macro from any thread.
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_IOStreamInterface
 * \sa SDL_StorageInterface
 * \sa SDL_VirtualJoystickDesc
 */
#define SDL_INIT_INTERFACE(iface)               \
    do {                                        \
        SDL_zerop(iface);                       \
        (iface)->version = sizeof(*(iface));    \
    } while (0)


#ifdef SDL_WIKI_DOCUMENTATION_SECTION

/**
 * Allocate memory on the stack (maybe).
 *
 * If SDL knows how to access alloca() on the current platform, it will use it
 * to stack-allocate memory here. If it doesn't, it will use SDL_malloc() to
 * heap-allocate memory.
 *
 * Since this might not be stack memory at all, it's important that you check
 * the returned pointer for NULL, and that you call SDL_stack_free on the
 * memory when done with it. Since this might be stack memory, it's important
 * that you don't allocate large amounts of it, or allocate in a loop without
 * returning from the function, so the stack doesn't overflow.
 *
 * \param type the datatype of the memory to allocate.
 * \param count the number of `type` objects to allocate.
 * \returns newly-allocated memory, or NULL on failure.
 *
 * \threadsafety It is safe to call this macro from any thread.
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_stack_free
 */
#define SDL_stack_alloc(type, count)    (type*)alloca(sizeof(type)*(count))

/**
 * Free memory previously allocated with SDL_stack_alloc.
 *
 * If SDL used alloca() to allocate this memory, this macro does nothing and
 * the allocated memory will be automatically released when the function that
 * called SDL_stack_alloc() returns. If SDL used SDL_malloc(), it will
 * SDL_free the memory immediately.
 *
 * \param data the pointer, from SDL_stack_alloc(), to free.
 *
 * \threadsafety It is safe to call this macro from any thread.
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_stack_alloc
 */
#define SDL_stack_free(data)
#elif !defined(SDL_DISABLE_ALLOCA)
#define SDL_stack_alloc(type, count)    (type*)alloca(sizeof(type)*(count))
#define SDL_stack_free(data)
#else
#define SDL_stack_alloc(type, count)    (type*)SDL_malloc(sizeof(type)*(count))
#define SDL_stack_free(data)            SDL_free(data)
#endif

/**
 * Allocate uninitialized memory.
 *
 * The allocated memory returned by this function must be freed with
 * SDL_free().
 *
 * If `size` is 0, it will be set to 1.
 *
 * If you want to allocate memory aligned to a specific alignment, consider
 * using SDL_aligned_alloc().
 *
 * \param size the size to allocate.
 * \returns a pointer to the allocated memory, or NULL if allocation failed.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_free
 * \sa SDL_calloc
 * \sa SDL_realloc
 * \sa SDL_aligned_alloc
 */
extern SDL_DECLSPEC SDL_MALLOC void * SDLCALL SDL_malloc(size_t size);

/**
 * Allocate a zero-initialized array.
 *
 * The memory returned by this function must be freed with SDL_free().
 *
 * If either of `nmemb` or `size` is 0, they will both be set to 1.
 *
 * \param nmemb the number of elements in the array.
 * \param size the size of each element of the array.
 * \returns a pointer to the allocated array, or NULL if allocation failed.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_free
 * \sa SDL_malloc
 * \sa SDL_realloc
 */
extern SDL_DECLSPEC SDL_MALLOC SDL_ALLOC_SIZE2(1, 2) void * SDLCALL SDL_calloc(size_t nmemb, size_t size);

/**
 * Change the size of allocated memory.
 *
 * The memory returned by this function must be freed with SDL_free().
 *
 * If `size` is 0, it will be set to 1. Note that this is unlike some other C
 * runtime `realloc` implementations, which may treat `realloc(mem, 0)` the
 * same way as `free(mem)`.
 *
 * If `mem` is NULL, the behavior of this function is equivalent to
 * SDL_malloc(). Otherwise, the function can have one of three possible
 * outcomes:
 *
 * - If it returns the same pointer as `mem`, it means that `mem` was resized
 *   in place without freeing.
 * - If it returns a different non-NULL pointer, it means that `mem` was freed
 *   and cannot be dereferenced anymore.
 * - If it returns NULL (indicating failure), then `mem` will remain valid and
 *   must still be freed with SDL_free().
 *
 * \param mem a pointer to allocated memory to reallocate, or NULL.
 * \param size the new size of the memory.
 * \returns a pointer to the newly allocated memory, or NULL if allocation
 *          failed.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_free
 * \sa SDL_malloc
 * \sa SDL_calloc
 */
extern SDL_DECLSPEC SDL_ALLOC_SIZE(2) void * SDLCALL SDL_realloc(void *mem, size_t size);

/**
 * Free allocated memory.
 *
 * The pointer is no longer valid after this call and cannot be dereferenced
 * anymore.
 *
 * If `mem` is NULL, this function does nothing.
 *
 * \param mem a pointer to allocated memory, or NULL.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_malloc
 * \sa SDL_calloc
 * \sa SDL_realloc
 */
extern SDL_DECLSPEC void SDLCALL SDL_free(void *mem);

/**
 * A callback used to implement SDL_malloc().
 *
 * SDL will always ensure that the passed `size` is greater than 0.
 *
 * \param size the size to allocate.
 * \returns a pointer to the allocated memory, or NULL if allocation failed.
 *
 * \threadsafety It should be safe to call this callback from any thread.
 *
 * \since This datatype is available since SDL 3.1.3.
 *
 * \sa SDL_malloc
 * \sa SDL_GetOriginalMemoryFunctions
 * \sa SDL_GetMemoryFunctions
 * \sa SDL_SetMemoryFunctions
 */
typedef void *(SDLCALL *SDL_malloc_func)(size_t size);

/**
 * A callback used to implement SDL_calloc().
 *
 * SDL will always ensure that the passed `nmemb` and `size` are both greater
 * than 0.
 *
 * \param nmemb the number of elements in the array.
 * \param size the size of each element of the array.
 * \returns a pointer to the allocated array, or NULL if allocation failed.
 *
 * \threadsafety It should be safe to call this callback from any thread.
 *
 * \since This datatype is available since SDL 3.1.3.
 *
 * \sa SDL_calloc
 * \sa SDL_GetOriginalMemoryFunctions
 * \sa SDL_GetMemoryFunctions
 * \sa SDL_SetMemoryFunctions
 */
typedef void *(SDLCALL *SDL_calloc_func)(size_t nmemb, size_t size);

/**
 * A callback used to implement SDL_realloc().
 *
 * SDL will always ensure that the passed `size` is greater than 0.
 *
 * \param mem a pointer to allocated memory to reallocate, or NULL.
 * \param size the new size of the memory.
 * \returns a pointer to the newly allocated memory, or NULL if allocation
 *          failed.
 *
 * \threadsafety It should be safe to call this callback from any thread.
 *
 * \since This datatype is available since SDL 3.1.3.
 *
 * \sa SDL_realloc
 * \sa SDL_GetOriginalMemoryFunctions
 * \sa SDL_GetMemoryFunctions
 * \sa SDL_SetMemoryFunctions
 */
typedef void *(SDLCALL *SDL_realloc_func)(void *mem, size_t size);

/**
 * A callback used to implement SDL_free().
 *
 * SDL will always ensure that the passed `mem` is a non-NULL pointer.
 *
 * \param mem a pointer to allocated memory.
 *
 * \threadsafety It should be safe to call this callback from any thread.
 *
 * \since This datatype is available since SDL 3.1.3.
 *
 * \sa SDL_free
 * \sa SDL_GetOriginalMemoryFunctions
 * \sa SDL_GetMemoryFunctions
 * \sa SDL_SetMemoryFunctions
 */
typedef void (SDLCALL *SDL_free_func)(void *mem);

/**
 * Get the original set of SDL memory functions.
 *
 * This is what SDL_malloc and friends will use by default, if there has been
 * no call to SDL_SetMemoryFunctions. This is not necessarily using the C
 * runtime's `malloc` functions behind the scenes! Different platforms and
 * build configurations might do any number of unexpected things.
 *
 * \param malloc_func filled with malloc function.
 * \param calloc_func filled with calloc function.
 * \param realloc_func filled with realloc function.
 * \param free_func filled with free function.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC void SDLCALL SDL_GetOriginalMemoryFunctions(SDL_malloc_func *malloc_func,
                                                            SDL_calloc_func *calloc_func,
                                                            SDL_realloc_func *realloc_func,
                                                            SDL_free_func *free_func);

/**
 * Get the current set of SDL memory functions.
 *
 * \param malloc_func filled with malloc function.
 * \param calloc_func filled with calloc function.
 * \param realloc_func filled with realloc function.
 * \param free_func filled with free function.
 *
 * \threadsafety This does not hold a lock, so do not call this in the
 *               unlikely event of a background thread calling
 *               SDL_SetMemoryFunctions simultaneously.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_SetMemoryFunctions
 * \sa SDL_GetOriginalMemoryFunctions
 */
extern SDL_DECLSPEC void SDLCALL SDL_GetMemoryFunctions(SDL_malloc_func *malloc_func,
                                                    SDL_calloc_func *calloc_func,
                                                    SDL_realloc_func *realloc_func,
                                                    SDL_free_func *free_func);

/**
 * Replace SDL's memory allocation functions with a custom set.
 *
 * It is not safe to call this function once any allocations have been made,
 * as future calls to SDL_free will use the new allocator, even if they came
 * from an SDL_malloc made with the old one!
 *
 * If used, usually this needs to be the first call made into the SDL library,
 * if not the very first thing done at program startup time.
 *
 * \param malloc_func custom malloc function.
 * \param calloc_func custom calloc function.
 * \param realloc_func custom realloc function.
 * \param free_func custom free function.
 * \returns true on success or false on failure; call SDL_GetError() for more
 *          information.
 *
 * \threadsafety It is safe to call this function from any thread, but one
 *               should not replace the memory functions once any allocations
 *               are made!
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_GetMemoryFunctions
 * \sa SDL_GetOriginalMemoryFunctions
 */
extern SDL_DECLSPEC bool SDLCALL SDL_SetMemoryFunctions(SDL_malloc_func malloc_func,
                                                            SDL_calloc_func calloc_func,
                                                            SDL_realloc_func realloc_func,
                                                            SDL_free_func free_func);

/**
 * Allocate memory aligned to a specific alignment.
 *
 * The memory returned by this function must be freed with SDL_aligned_free(),
 * _not_ SDL_free().
 *
 * If `alignment` is less than the size of `void *`, it will be increased to
 * match that.
 *
 * The returned memory address will be a multiple of the alignment value, and
 * the size of the memory allocated will be a multiple of the alignment value.
 *
 * \param alignment the alignment of the memory.
 * \param size the size to allocate.
 * \returns a pointer to the aligned memory, or NULL if allocation failed.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_aligned_free
 */
extern SDL_DECLSPEC SDL_MALLOC void * SDLCALL SDL_aligned_alloc(size_t alignment, size_t size);

/**
 * Free memory allocated by SDL_aligned_alloc().
 *
 * The pointer is no longer valid after this call and cannot be dereferenced
 * anymore.
 *
 * If `mem` is NULL, this function does nothing.
 *
 * \param mem a pointer previously returned by SDL_aligned_alloc(), or NULL.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_aligned_alloc
 */
extern SDL_DECLSPEC void SDLCALL SDL_aligned_free(void *mem);

/**
 * Get the number of outstanding (unfreed) allocations.
 *
 * \returns the number of allocations.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_GetNumAllocations(void);

/**
 * A thread-safe set of environment variables
 *
 * \since This struct is available since SDL 3.1.3.
 *
 * \sa SDL_GetEnvironment
 * \sa SDL_CreateEnvironment
 * \sa SDL_GetEnvironmentVariable
 * \sa SDL_GetEnvironmentVariables
 * \sa SDL_SetEnvironmentVariable
 * \sa SDL_UnsetEnvironmentVariable
 * \sa SDL_DestroyEnvironment
 */
typedef struct SDL_Environment SDL_Environment;

/**
 * Get the process environment.
 *
 * This is initialized at application start and is not affected by setenv()
 * and unsetenv() calls after that point. Use SDL_SetEnvironmentVariable() and
 * SDL_UnsetEnvironmentVariable() if you want to modify this environment, or
 * SDL_setenv_unsafe() or SDL_unsetenv_unsafe() if you want changes to persist
 * in the C runtime environment after SDL_Quit().
 *
 * \returns a pointer to the environment for the process or NULL on failure;
 *          call SDL_GetError() for more information.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_GetEnvironmentVariable
 * \sa SDL_GetEnvironmentVariables
 * \sa SDL_SetEnvironmentVariable
 * \sa SDL_UnsetEnvironmentVariable
 */
extern SDL_DECLSPEC SDL_Environment * SDLCALL SDL_GetEnvironment(void);

/**
 * Create a set of environment variables
 *
 * \param populated true to initialize it from the C runtime environment,
 *                  false to create an empty environment.
 * \returns a pointer to the new environment or NULL on failure; call
 *          SDL_GetError() for more information.
 *
 * \threadsafety If `populated` is false, it is safe to call this function
 *               from any thread, otherwise it is safe if no other threads are
 *               calling setenv() or unsetenv()
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_GetEnvironmentVariable
 * \sa SDL_GetEnvironmentVariables
 * \sa SDL_SetEnvironmentVariable
 * \sa SDL_UnsetEnvironmentVariable
 * \sa SDL_DestroyEnvironment
 */
extern SDL_DECLSPEC SDL_Environment * SDLCALL SDL_CreateEnvironment(bool populated);

/**
 * Get the value of a variable in the environment.
 *
 * \param env the environment to query.
 * \param name the name of the variable to get.
 * \returns a pointer to the value of the variable or NULL if it can't be
 *          found.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_GetEnvironment
 * \sa SDL_CreateEnvironment
 * \sa SDL_GetEnvironmentVariables
 * \sa SDL_SetEnvironmentVariable
 * \sa SDL_UnsetEnvironmentVariable
 */
extern SDL_DECLSPEC const char * SDLCALL SDL_GetEnvironmentVariable(SDL_Environment *env, const char *name);

/**
 * Get all variables in the environment.
 *
 * \param env the environment to query.
 * \returns a NULL terminated array of pointers to environment variables in
 *          the form "variable=value" or NULL on failure; call SDL_GetError()
 *          for more information. This is a single allocation that should be
 *          freed with SDL_free() when it is no longer needed.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_GetEnvironment
 * \sa SDL_CreateEnvironment
 * \sa SDL_GetEnvironmentVariables
 * \sa SDL_SetEnvironmentVariable
 * \sa SDL_UnsetEnvironmentVariable
 */
extern SDL_DECLSPEC char ** SDLCALL SDL_GetEnvironmentVariables(SDL_Environment *env);

/**
 * Set the value of a variable in the environment.
 *
 * \param env the environment to modify.
 * \param name the name of the variable to set.
 * \param value the value of the variable to set.
 * \param overwrite true to overwrite the variable if it exists, false to
 *                  return success without setting the variable if it already
 *                  exists.
 * \returns true on success or false on failure; call SDL_GetError() for more
 *          information.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_GetEnvironment
 * \sa SDL_CreateEnvironment
 * \sa SDL_GetEnvironmentVariable
 * \sa SDL_GetEnvironmentVariables
 * \sa SDL_UnsetEnvironmentVariable
 */
extern SDL_DECLSPEC bool SDLCALL SDL_SetEnvironmentVariable(SDL_Environment *env, const char *name, const char *value, bool overwrite);

/**
 * Clear a variable from the environment.
 *
 * \param env the environment to modify.
 * \param name the name of the variable to unset.
 * \returns true on success or false on failure; call SDL_GetError() for more
 *          information.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_GetEnvironment
 * \sa SDL_CreateEnvironment
 * \sa SDL_GetEnvironmentVariable
 * \sa SDL_GetEnvironmentVariables
 * \sa SDL_SetEnvironmentVariable
 * \sa SDL_UnsetEnvironmentVariable
 */
extern SDL_DECLSPEC bool SDLCALL SDL_UnsetEnvironmentVariable(SDL_Environment *env, const char *name);

/**
 * Destroy a set of environment variables.
 *
 * \param env the environment to destroy.
 *
 * \threadsafety It is safe to call this function from any thread, as long as
 *               the environment is no longer in use.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_CreateEnvironment
 */
extern SDL_DECLSPEC void SDLCALL SDL_DestroyEnvironment(SDL_Environment *env);

/**
 * Get the value of a variable in the environment.
 *
 * This function uses SDL's cached copy of the environment and is thread-safe.
 *
 * \param name the name of the variable to get.
 * \returns a pointer to the value of the variable or NULL if it can't be
 *          found.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC const char * SDLCALL SDL_getenv(const char *name);

/**
 * Get the value of a variable in the environment.
 *
 * This function bypasses SDL's cached copy of the environment and is not
 * thread-safe.
 *
 * \param name the name of the variable to get.
 * \returns a pointer to the value of the variable or NULL if it can't be
 *          found.
 *
 * \threadsafety This function is not thread safe, consider using SDL_getenv()
 *               instead.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_getenv
 */
extern SDL_DECLSPEC const char * SDLCALL SDL_getenv_unsafe(const char *name);

/**
 * Set the value of a variable in the environment.
 *
 * \param name the name of the variable to set.
 * \param value the value of the variable to set.
 * \param overwrite 1 to overwrite the variable if it exists, 0 to return
 *                  success without setting the variable if it already exists.
 * \returns 0 on success, -1 on error.
 *
 * \threadsafety This function is not thread safe, consider using
 *               SDL_SetEnvironmentVariable() instead.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_SetEnvironmentVariable
 */
extern SDL_DECLSPEC int SDLCALL SDL_setenv_unsafe(const char *name, const char *value, int overwrite);

/**
 * Clear a variable from the environment.
 *
 * \param name the name of the variable to unset.
 * \returns 0 on success, -1 on error.
 *
 * \threadsafety This function is not thread safe, consider using
 *               SDL_UnsetEnvironmentVariable() instead.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_UnsetEnvironmentVariable
 */
extern SDL_DECLSPEC int SDLCALL SDL_unsetenv_unsafe(const char *name);

/**
 * A callback used with SDL sorting and binary search functions.
 *
 * \param a a pointer to the first element being compared.
 * \param b a pointer to the second element being compared.
 * \returns -1 if `a` should be sorted before `b`, 1 if `b` should be sorted
 *          before `a`, 0 if they are equal. If two elements are equal, their
 *          order in the sorted array is undefined.
 *
 * \since This callback is available since SDL 3.1.3.
 *
 * \sa SDL_bsearch
 * \sa SDL_qsort
 */
typedef int (SDLCALL *SDL_CompareCallback)(const void *a, const void *b);

/**
 * Sort an array.
 *
 * For example:
 *
 * ```c
 * typedef struct {
 *     int key;
 *     const char *string;
 * } data;
 *
 * int SDLCALL compare(const void *a, const void *b)
 * {
 *     const data *A = (const data *)a;
 *     const data *B = (const data *)b;
 *
 *     if (A->n < B->n) {
 *         return -1;
 *     } else if (B->n < A->n) {
 *         return 1;
 *     } else {
 *         return 0;
 *     }
 * }
 *
 * data values[] = {
 *     { 3, "third" }, { 1, "first" }, { 2, "second" }
 * };
 *
 * SDL_qsort(values, SDL_arraysize(values), sizeof(values[0]), compare);
 * ```
 *
 * \param base a pointer to the start of the array.
 * \param nmemb the number of elements in the array.
 * \param size the size of the elements in the array.
 * \param compare a function used to compare elements in the array.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_bsearch
 * \sa SDL_qsort_r
 */
extern SDL_DECLSPEC void SDLCALL SDL_qsort(void *base, size_t nmemb, size_t size, SDL_CompareCallback compare);

/**
 * Perform a binary search on a previously sorted array.
 *
 * For example:
 *
 * ```c
 * typedef struct {
 *     int key;
 *     const char *string;
 * } data;
 *
 * int SDLCALL compare(const void *a, const void *b)
 * {
 *     const data *A = (const data *)a;
 *     const data *B = (const data *)b;
 *
 *     if (A->n < B->n) {
 *         return -1;
 *     } else if (B->n < A->n) {
 *         return 1;
 *     } else {
 *         return 0;
 *     }
 * }
 *
 * data values[] = {
 *     { 1, "first" }, { 2, "second" }, { 3, "third" }
 * };
 * data key = { 2, NULL };
 *
 * data *result = SDL_bsearch(&key, values, SDL_arraysize(values), sizeof(values[0]), compare);
 * ```
 *
 * \param key a pointer to a key equal to the element being searched for.
 * \param base a pointer to the start of the array.
 * \param nmemb the number of elements in the array.
 * \param size the size of the elements in the array.
 * \param compare a function used to compare elements in the array.
 * \returns a pointer to the matching element in the array, or NULL if not
 *          found.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_bsearch_r
 * \sa SDL_qsort
 */
extern SDL_DECLSPEC void * SDLCALL SDL_bsearch(const void *key, const void *base, size_t nmemb, size_t size, SDL_CompareCallback compare);

/**
 * A callback used with SDL sorting and binary search functions.
 *
 * \param userdata the `userdata` pointer passed to the sort function.
 * \param a a pointer to the first element being compared.
 * \param b a pointer to the second element being compared.
 * \returns -1 if `a` should be sorted before `b`, 1 if `b` should be sorted
 *          before `a`, 0 if they are equal. If two elements are equal, their
 *          order in the sorted array is undefined.
 *
 * \since This callback is available since SDL 3.1.3.
 *
 * \sa SDL_qsort_r
 * \sa SDL_bsearch_r
 */
typedef int (SDLCALL *SDL_CompareCallback_r)(void *userdata, const void *a, const void *b);

/**
 * Sort an array, passing a userdata pointer to the compare function.
 *
 * For example:
 *
 * ```c
 * typedef enum {
 *     sort_increasing,
 *     sort_decreasing,
 * } sort_method;
 *
 * typedef struct {
 *     int key;
 *     const char *string;
 * } data;
 *
 * int SDLCALL compare(const void *userdata, const void *a, const void *b)
 * {
 *     sort_method method = (sort_method)(uintptr_t)userdata;
 *     const data *A = (const data *)a;
 *     const data *B = (const data *)b;
 *
 *     if (A->key < B->key) {
 *         return (method == sort_increasing) ? -1 : 1;
 *     } else if (B->key < A->key) {
 *         return (method == sort_increasing) ? 1 : -1;
 *     } else {
 *         return 0;
 *     }
 * }
 *
 * data values[] = {
 *     { 3, "third" }, { 1, "first" }, { 2, "second" }
 * };
 *
 * SDL_qsort_r(values, SDL_arraysize(values), sizeof(values[0]), compare, (const void *)(uintptr_t)sort_increasing);
 * ```
 *
 * \param base a pointer to the start of the array.
 * \param nmemb the number of elements in the array.
 * \param size the size of the elements in the array.
 * \param compare a function used to compare elements in the array.
 * \param userdata a pointer to pass to the compare function.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_bsearch_r
 * \sa SDL_qsort
 */
extern SDL_DECLSPEC void SDLCALL SDL_qsort_r(void *base, size_t nmemb, size_t size, SDL_CompareCallback_r compare, void *userdata);

/**
 * Perform a binary search on a previously sorted array, passing a userdata
 * pointer to the compare function.
 *
 * For example:
 *
 * ```c
 * typedef enum {
 *     sort_increasing,
 *     sort_decreasing,
 * } sort_method;
 *
 * typedef struct {
 *     int key;
 *     const char *string;
 * } data;
 *
 * int SDLCALL compare(const void *userdata, const void *a, const void *b)
 * {
 *     sort_method method = (sort_method)(uintptr_t)userdata;
 *     const data *A = (const data *)a;
 *     const data *B = (const data *)b;
 *
 *     if (A->key < B->key) {
 *         return (method == sort_increasing) ? -1 : 1;
 *     } else if (B->key < A->key) {
 *         return (method == sort_increasing) ? 1 : -1;
 *     } else {
 *         return 0;
 *     }
 * }
 *
 * data values[] = {
 *     { 1, "first" }, { 2, "second" }, { 3, "third" }
 * };
 * data key = { 2, NULL };
 *
 * data *result = SDL_bsearch_r(&key, values, SDL_arraysize(values), sizeof(values[0]), compare, (const void *)(uintptr_t)sort_increasing);
 * ```
 *
 * \param key a pointer to a key equal to the element being searched for.
 * \param base a pointer to the start of the array.
 * \param nmemb the number of elements in the array.
 * \param size the size of the elements in the array.
 * \param compare a function used to compare elements in the array.
 * \param userdata a pointer to pass to the compare function.
 * \returns a pointer to the matching element in the array, or NULL if not
 *          found.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_bsearch
 * \sa SDL_qsort_r
 */
extern SDL_DECLSPEC void * SDLCALL SDL_bsearch_r(const void *key, const void *base, size_t nmemb, size_t size, SDL_CompareCallback_r compare, void *userdata);

/**
 * Compute the absolute value of `x`.
 *
 * \param x an integer value.
 * \returns the absolute value of x.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_abs(int x);

/**
 * Return the lesser of two values.
 *
 * This is a helper macro that might be more clear than writing out the
 * comparisons directly, and works with any type that can be compared with the
 * `<` operator. However, it double-evaluates both its parameters, so do not
 * use expressions with side-effects here.
 *
 * \param x the first value to compare.
 * \param y the second value to compare.
 * \returns the lesser of `x` and `y`.
 *
 * \threadsafety It is safe to call this macro from any thread.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_min(x, y) (((x) < (y)) ? (x) : (y))

/**
 * Return the greater of two values.
 *
 * This is a helper macro that might be more clear than writing out the
 * comparisons directly, and works with any type that can be compared with the
 * `>` operator. However, it double-evaluates both its parameters, so do not
 * use expressions with side-effects here.
 *
 * \param x the first value to compare.
 * \param y the second value to compare.
 * \returns the lesser of `x` and `y`.
 *
 * \threadsafety It is safe to call this macro from any thread.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_max(x, y) (((x) > (y)) ? (x) : (y))

/**
 * Return a value clamped to a range.
 *
 * If `x` is outside the range a values between `a` and `b`, the returned
 * value will be `a` or `b` as appropriate. Otherwise, `x` is returned.
 *
 * This macro will produce incorrect results if `b` is less than `a`.
 *
 * This is a helper macro that might be more clear than writing out the
 * comparisons directly, and works with any type that can be compared with the
 * `<` and `>` operators. However, it double-evaluates all its parameters, so
 * do not use expressions with side-effects here.
 *
 * \param x the value to compare.
 * \param a the low end value.
 * \param b the high end value.
 * \returns x, clamped between a and b.
 *
 * \threadsafety It is safe to call this macro from any thread.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_clamp(x, a, b) (((x) < (a)) ? (a) : (((x) > (b)) ? (b) : (x)))

/**
 * Query if a character is alphabetic (a letter).
 *
 * **WARNING**: Regardless of system locale, this will only treat ASCII values
 * for English 'a-z' and 'A-Z' as true.
 *
 * \param x character value to check.
 * \returns non-zero if x falls within the character class, zero otherwise.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_isalpha(int x);

/**
 * Query if a character is alphabetic (a letter) or a number.
 *
 * **WARNING**: Regardless of system locale, this will only treat ASCII values
 * for English 'a-z', 'A-Z', and '0-9' as true.
 *
 * \param x character value to check.
 * \returns non-zero if x falls within the character class, zero otherwise.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_isalnum(int x);

/**
 * Report if a character is blank (a space or tab).
 *
 * **WARNING**: Regardless of system locale, this will only treat ASCII values
 * 0x20 (space) or 0x9 (tab) as true.
 *
 * \param x character value to check.
 * \returns non-zero if x falls within the character class, zero otherwise.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_isblank(int x);

/**
 * Report if a character is a control character.
 *
 * **WARNING**: Regardless of system locale, this will only treat ASCII values
 * 0 through 0x1F, and 0x7F, as true.
 *
 * \param x character value to check.
 * \returns non-zero if x falls within the character class, zero otherwise.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_iscntrl(int x);

/**
 * Report if a character is a numeric digit.
 *
 * **WARNING**: Regardless of system locale, this will only treat ASCII values
 * '0' (0x30) through '9' (0x39), as true.
 *
 * \param x character value to check.
 * \returns non-zero if x falls within the character class, zero otherwise.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_isdigit(int x);

/**
 * Report if a character is a hexadecimal digit.
 *
 * **WARNING**: Regardless of system locale, this will only treat ASCII values
 * 'A' through 'F', 'a' through 'f', and '0' through '9', as true.
 *
 * \param x character value to check.
 * \returns non-zero if x falls within the character class, zero otherwise.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_isxdigit(int x);

/**
 * Report if a character is a punctuation mark.
 *
 * **WARNING**: Regardless of system locale, this is equivalent to
 * `((SDL_isgraph(x)) && (!SDL_isalnum(x)))`.
 *
 * \param x character value to check.
 * \returns non-zero if x falls within the character class, zero otherwise.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_isgraph
 * \sa SDL_isalnum
 */
extern SDL_DECLSPEC int SDLCALL SDL_ispunct(int x);

/**
 * Report if a character is whitespace.
 *
 * **WARNING**: Regardless of system locale, this will only treat the
 * following ASCII values as true:
 *
 * - space (0x20)
 * - tab (0x09)
 * - newline (0x0A)
 * - vertical tab (0x0B)
 * - form feed (0x0C)
 * - return (0x0D)
 *
 * \param x character value to check.
 * \returns non-zero if x falls within the character class, zero otherwise.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_isspace(int x);

/**
 * Report if a character is upper case.
 *
 * **WARNING**: Regardless of system locale, this will only treat ASCII values
 * 'A' through 'Z' as true.
 *
 * \param x character value to check.
 * \returns non-zero if x falls within the character class, zero otherwise.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_isupper(int x);

/**
 * Report if a character is lower case.
 *
 * **WARNING**: Regardless of system locale, this will only treat ASCII values
 * 'a' through 'z' as true.
 *
 * \param x character value to check.
 * \returns non-zero if x falls within the character class, zero otherwise.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_islower(int x);

/**
 * Report if a character is "printable".
 *
 * Be advised that "printable" has a definition that goes back to text
 * terminals from the dawn of computing, making this a sort of special case
 * function that is not suitable for Unicode (or most any) text management.
 *
 * **WARNING**: Regardless of system locale, this will only treat ASCII values
 * ' ' (0x20) through '~' (0x7E) as true.
 *
 * \param x character value to check.
 * \returns non-zero if x falls within the character class, zero otherwise.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_isprint(int x);

/**
 * Report if a character is any "printable" except space.
 *
 * Be advised that "printable" has a definition that goes back to text
 * terminals from the dawn of computing, making this a sort of special case
 * function that is not suitable for Unicode (or most any) text management.
 *
 * **WARNING**: Regardless of system locale, this is equivalent to
 * `(SDL_isprint(x)) && ((x) != ' ')`.
 *
 * \param x character value to check.
 * \returns non-zero if x falls within the character class, zero otherwise.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_isprint
 */
extern SDL_DECLSPEC int SDLCALL SDL_isgraph(int x);

/**
 * Convert low-ASCII English letters to uppercase.
 *
 * **WARNING**: Regardless of system locale, this will only convert ASCII
 * values 'a' through 'z' to uppercase.
 *
 * This function returns the uppercase equivalent of `x`. If a character
 * cannot be converted, or is already uppercase, this function returns `x`.
 *
 * \param x character value to check.
 * \returns capitalized version of x, or x if no conversion available.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_toupper(int x);

/**
 * Convert low-ASCII English letters to lowercase.
 *
 * **WARNING**: Regardless of system locale, this will only convert ASCII
 * values 'A' through 'Z' to lowercase.
 *
 * This function returns the lowercase equivalent of `x`. If a character
 * cannot be converted, or is already lowercase, this function returns `x`.
 *
 * \param x character value to check.
 * \returns lowercase version of x, or x if no conversion available.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_tolower(int x);

/**
 * Calculate a CRC-16 value.
 *
 * https://en.wikipedia.org/wiki/Cyclic_redundancy_check
 *
 * This function can be called multiple times, to stream data to be
 * checksummed in blocks. Each call must provide the previous CRC-16 return
 * value to be updated with the next block. The first call to this function
 * for a set of blocks should pass in a zero CRC value.
 *
 * \param crc the current checksum for this data set, or 0 for a new data set.
 * \param data a new block of data to add to the checksum.
 * \param len the size, in bytes, of the new block of data.
 * \returns a CRC-16 checksum value of all blocks in the data set.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC Uint16 SDLCALL SDL_crc16(Uint16 crc, const void *data, size_t len);

/**
 * Calculate a CRC-32 value.
 *
 * https://en.wikipedia.org/wiki/Cyclic_redundancy_check
 *
 * This function can be called multiple times, to stream data to be
 * checksummed in blocks. Each call must provide the previous CRC-32 return
 * value to be updated with the next block. The first call to this function
 * for a set of blocks should pass in a zero CRC value.
 *
 * \param crc the current checksum for this data set, or 0 for a new data set.
 * \param data a new block of data to add to the checksum.
 * \param len the size, in bytes, of the new block of data.
 * \returns a CRC-32 checksum value of all blocks in the data set.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC Uint32 SDLCALL SDL_crc32(Uint32 crc, const void *data, size_t len);

/**
 * Calculate a 32-bit MurmurHash3 value for a block of data.
 *
 * https://en.wikipedia.org/wiki/MurmurHash
 *
 * A seed may be specified, which changes the final results consistently, but
 * this does not work like SDL_crc16 and SDL_crc32: you can't feed a previous
 * result from this function back into itself as the next seed value to
 * calculate a hash in chunks; it won't produce the same hash as it would if
 * the same data was provided in a single call.
 *
 * If you aren't sure what to provide for a seed, zero is fine. Murmur3 is not
 * cryptographically secure, so it shouldn't be used for hashing top-secret
 * data.
 *
 * \param data the data to be hashed.
 * \param len the size of data, in bytes.
 * \param seed a value that alters the final hash value.
 * \returns a Murmur3 32-bit hash value.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC Uint32 SDLCALL SDL_murmur3_32(const void *data, size_t len, Uint32 seed);

/**
 * Copy non-overlapping memory.
 *
 * The memory regions must not overlap. If they do, use SDL_memmove() instead.
 *
 * \param dst The destination memory region. Must not be NULL, and must not
 *            overlap with `src`.
 * \param src The source memory region. Must not be NULL, and must not overlap
 *            with `dst`.
 * \param len The length in bytes of both `dst` and `src`.
 * \returns `dst`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_memmove
 */
extern SDL_DECLSPEC void * SDLCALL SDL_memcpy(SDL_OUT_BYTECAP(len) void *dst, SDL_IN_BYTECAP(len) const void *src, size_t len);

/* Take advantage of compiler optimizations for memcpy */
#ifndef SDL_SLOW_MEMCPY
#ifdef SDL_memcpy
#undef SDL_memcpy
#endif
#define SDL_memcpy  memcpy
#endif


/**
 * A macro to copy memory between objects, with basic type checking.
 *
 * SDL_memcpy and SDL_memmove do not care where you copy memory to and from,
 * which can lead to bugs. This macro aims to avoid most of those bugs by
 * making sure that the source and destination are both pointers to objects
 * that are the same size. It does not check that the objects are the same
 * _type_, just that the copy will not overflow either object.
 *
 * The size check happens at compile time, and the compiler will throw an
 * error if the objects are different sizes.
 *
 * Generally this is intended to copy a single object, not an array.
 *
 * This macro looks like it double-evaluates its parameters, but the extras
 * them are in `sizeof` sections, which generate no code nor side-effects.
 *
 * \param dst a pointer to the destination object. Must not be NULL.
 * \param src a pointer to the source object. Must not be NULL.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
#define SDL_copyp(dst, src)                                                                 \
    { SDL_COMPILE_TIME_ASSERT(SDL_copyp, sizeof (*(dst)) == sizeof (*(src))); }             \
    SDL_memcpy((dst), (src), sizeof(*(src)))

/**
 * Copy memory ranges that might overlap.
 *
 * It is okay for the memory regions to overlap. If you are confident that the
 * regions never overlap, using SDL_memcpy() may improve performance.
 *
 * \param dst The destination memory region. Must not be NULL.
 * \param src The source memory region. Must not be NULL.
 * \param len The length in bytes of both `dst` and `src`.
 * \returns `dst`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_memcpy
 */
extern SDL_DECLSPEC void * SDLCALL SDL_memmove(SDL_OUT_BYTECAP(len) void *dst, SDL_IN_BYTECAP(len) const void *src, size_t len);

/* Take advantage of compiler optimizations for memmove */
#ifndef SDL_SLOW_MEMMOVE
#ifdef SDL_memmove
#undef SDL_memmove
#endif
#define SDL_memmove memmove
#endif

/**
 * Initialize all bytes of buffer of memory to a specific value.
 *
 * This function will set `len` bytes, pointed to by `dst`, to the value
 * specified in `c`.
 *
 * Despite `c` being an `int` instead of a `char`, this only operates on
 * bytes; `c` must be a value between 0 and 255, inclusive.
 *
 * \param dst the destination memory region. Must not be NULL.
 * \param c the byte value to set.
 * \param len the length, in bytes, to set in `dst`.
 * \returns `dst`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC void * SDLCALL SDL_memset(SDL_OUT_BYTECAP(len) void *dst, int c, size_t len);

/**
 * Initialize all 32-bit words of buffer of memory to a specific value.
 *
 * This function will set a buffer of `dwords` Uint32 values, pointed to by
 * `dst`, to the value specified in `val`.
 *
 * Unlike SDL_memset, this sets 32-bit values, not bytes, so it's not limited
 * to a range of 0-255.
 *
 * \param dst the destination memory region. Must not be NULL.
 * \param val the Uint32 value to set.
 * \param dwords the number of Uint32 values to set in `dst`.
 * \returns `dst`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC void * SDLCALL SDL_memset4(void *dst, Uint32 val, size_t dwords);

/* Take advantage of compiler optimizations for memset */
#ifndef SDL_SLOW_MEMSET
#ifdef SDL_memset
#undef SDL_memset
#endif
#define SDL_memset  memset
#endif

/**
 * Clear an object's memory to zero.
 *
 * This is wrapper over SDL_memset that handles calculating the object size,
 * so there's no chance of copy/paste errors, and the code is cleaner.
 *
 * This requires an object, not a pointer to an object, nor an array.
 *
 * \param x the object to clear.
 *
 * \threadsafety It is safe to call this macro from any thread.
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_zerop
 * \sa SDL_zeroa
 */
#define SDL_zero(x) SDL_memset(&(x), 0, sizeof((x)))

/**
 * Clear an object's memory to zero, using a pointer.
 *
 * This is wrapper over SDL_memset that handles calculating the object size,
 * so there's no chance of copy/paste errors, and the code is cleaner.
 *
 * This requires a pointer to an object, not an object itself, nor an array.
 *
 * \param x a pointer to the object to clear.
 *
 * \threadsafety It is safe to call this macro from any thread.
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_zero
 * \sa SDL_zeroa
 */
#define SDL_zerop(x) SDL_memset((x), 0, sizeof(*(x)))

/**
 * Clear an array's memory to zero.
 *
 * This is wrapper over SDL_memset that handles calculating the array size, so
 * there's no chance of copy/paste errors, and the code is cleaner.
 *
 * This requires an array, not an object, nor a pointer to an object.
 *
 * \param x an array to clear.
 *
 * \threadsafety It is safe to call this macro from any thread.
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_zero
 * \sa SDL_zeroa
 */
#define SDL_zeroa(x) SDL_memset((x), 0, sizeof((x)))


/**
 * Compare two buffers of memory.
 *
 * \param s1 the first buffer to compare. NULL is not permitted!
 * \param s2 the second buffer to compare. NULL is not permitted!
 * \param len the number of bytes to compare between the buffers.
 * \returns less than zero if s1 is "less than" s2, greater than zero if
 *          s1 is "greater than" s2, and zero if the buffers match
 *          exactly for `len` bytes.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_memcmp(const void *s1, const void *s2, size_t len);

/**
 * This works exactly like wcslen() but doesn't require access to a C runtime.
 *
 * Counts the number of wchar_t values in `wstr`, excluding the null
 * terminator.
 *
 * Like SDL_strlen only counts bytes and not codepoints in a UTF-8 string,
 * this counts wchar_t values in a string, even if the string's encoding is of
 * variable width, like UTF-16.
 *
 * Also be aware that wchar_t is different sizes on different platforms (4
 * bytes on Linux, 2 on Windows, etc).
 *
 * \param wstr The null-terminated wide string to read. Must not be NULL.
 * \returns the length (in wchar_t values, excluding the null terminator) of `wstr`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_wcsnlen
 * \sa SDL_utf8strlen
 * \sa SDL_utf8strnlen
 */
extern SDL_DECLSPEC size_t SDLCALL SDL_wcslen(const wchar_t *wstr);

/**
 * This works exactly like wcsnlen() but doesn't require access to a C
 * runtime.
 *
 * Counts up to a maximum of `maxlen` wchar_t values in `wstr`, excluding the
 * null terminator.
 *
 * Like SDL_strnlen only counts bytes and not codepoints in a UTF-8 string,
 * this counts wchar_t values in a string, even if the string's encoding is of
 * variable width, like UTF-16.
 *
 * Also be aware that wchar_t is different sizes on different platforms (4
 * bytes on Linux, 2 on Windows, etc).
 *
 * Also, `maxlen` is a count of wide characters, not bytes!
 *
 * \param wstr The null-terminated wide string to read. Must not be NULL.
 * \param maxlen The maximum amount of wide characters to count.
 * \returns the length (in wide characters, excluding the null terminator) of
 *          `wstr` but never more than `maxlen`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_wcslen
 * \sa SDL_utf8strlen
 * \sa SDL_utf8strnlen
 */
extern SDL_DECLSPEC size_t SDLCALL SDL_wcsnlen(const wchar_t *wstr, size_t maxlen);

/**
 * Copy a wide string.
 *
 * This function copies `maxlen` - 1 wide characters from `src` to `dst`, then
 * appends a null terminator.
 *
 * `src` and `dst` must not overlap.
 *
 * If `maxlen` is 0, no wide characters are copied and no null terminator is
 * written.
 *
 * \param dst The destination buffer. Must not be NULL, and must not overlap
 *            with `src`.
 * \param src The null-terminated wide string to copy. Must not be NULL, and
 *            must not overlap with `dst`.
 * \param maxlen The length (in wide characters) of the destination buffer.
 * \returns the length (in wide characters, excluding the null terminator) of
 *          `src`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_wcslcat
 */
extern SDL_DECLSPEC size_t SDLCALL SDL_wcslcpy(SDL_OUT_Z_CAP(maxlen) wchar_t *dst, const wchar_t *src, size_t maxlen);

/**
 * Concatenate wide strings.
 *
 * This function appends up to `maxlen` - SDL_wcslen(dst) - 1 wide characters
 * from `src` to the end of the wide string in `dst`, then appends a null
 * terminator.
 *
 * `src` and `dst` must not overlap.
 *
 * If `maxlen` - SDL_wcslen(dst) - 1 is less than or equal to 0, then `dst` is
 * unmodified.
 *
 * \param dst The destination buffer already containing the first
 *            null-terminated wide string. Must not be NULL and must not
 *            overlap with `src`.
 * \param src The second null-terminated wide string. Must not be NULL, and
 *            must not overlap with `dst`.
 * \param maxlen The length (in wide characters) of the destination buffer.
 * \returns the length (in wide characters, excluding the null terminator) of
 *          the string in `dst` plus the length of `src`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_wcslcpy
 */
extern SDL_DECLSPEC size_t SDLCALL SDL_wcslcat(SDL_INOUT_Z_CAP(maxlen) wchar_t *dst, const wchar_t *src, size_t maxlen);

/**
 * Allocate a copy of a wide string.
 *
 * This allocates enough space for a null-terminated copy of `wstr`, using
 * SDL_malloc, and then makes a copy of the string into this space.
 *
 * The returned string is owned by the caller, and should be passed to
 * SDL_free when no longer needed.
 *
 * \param wstr the string to copy.
 * \returns a pointer to the newly-allocated wide string.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC wchar_t * SDLCALL SDL_wcsdup(const wchar_t *wstr);

/**
 * Search a wide string for the first instance of a specific substring.
 *
 * The search ends once it finds the requested substring, or a null
 * terminator byte to end the string.
 *
 * Note that this looks for strings of _wide characters_, not _codepoints_, so
 * it's legal to search for malformed and incomplete UTF-16 sequences.
 *
 * \param haystack the wide string to search. Must not be NULL.
 * \param needle the wide string to search for. Must not be NULL.
 * \returns a pointer to the first instance of `needle` in the string, or NULL if not found.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC wchar_t * SDLCALL SDL_wcsstr(const wchar_t *haystack, const wchar_t *needle);

/**
 * Search a wide string, up to n wide chars, for the first instance of a specific substring.
 *
 * The search ends once it finds the requested substring, or a null
 * terminator value to end the string, or `maxlen` wide character have been
 * examined. It is possible to use this function on a wide string without a
 * null terminator.
 *
 * Note that this looks for strings of _wide characters_, not _codepoints_, so
 * it's legal to search for malformed and incomplete UTF-16 sequences.
 *
 * \param haystack the wide string to search. Must not be NULL.
 * \param needle the wide string to search for. Must not be NULL.
 * \param maxlen the maximum number of wide characters to search in `haystack`.
 * \returns a pointer to the first instance of `needle` in the string, or NULL if not found.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC wchar_t * SDLCALL SDL_wcsnstr(const wchar_t *haystack, const wchar_t *needle, size_t maxlen);

/**
 * Compare two null-terminated wide strings.
 *
 * This only compares wchar_t values until it hits a null-terminating
 * character; it does not care if the string is well-formed UTF-16 (or UTF-32,
 * depending on your platform's wchar_t size), or uses valid Unicode values.
 *
 * \param str1 the first string to compare. NULL is not permitted!
 * \param str2 the second string to compare. NULL is not permitted!
 * \returns less than zero if str1 is "less than" str2, greater than zero if
 *          str1 is "greater than" str2, and zero if the strings match
 *          exactly.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_wcscmp(const wchar_t *str1, const wchar_t *str2);

/**
 * Compare two wide strings up to a number of wchar_t values.
 *
 * This only compares wchar_t values; it does not care if the string is
 * well-formed UTF-16 (or UTF-32, depending on your platform's wchar_t size),
 * or uses valid Unicode values.
 *
 * Note that while this function is intended to be used with UTF-16 (or
 * UTF-32, depending on your platform's definition of wchar_t), it is
 * comparing raw wchar_t values and not Unicode codepoints: `maxlen` specifies
 * a wchar_t limit! If the limit lands in the middle of a multi-wchar UTF-16
 * sequence, it will only compare a portion of the final character.
 *
 * `maxlen` specifies a maximum number of wchar_t to compare; if the strings
 * match to this number of wide chars (or both have matched to a
 * null-terminator character before this count), they will be considered
 * equal.
 *
 * \param str1 the first string to compare. NULL is not permitted!
 * \param str2 the second string to compare. NULL is not permitted!
 * \param maxlen the maximum number of wchar_t to compare.
 * \returns less than zero if str1 is "less than" str2, greater than zero if
 *          str1 is "greater than" str2, and zero if the strings match
 *          exactly.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_wcsncmp(const wchar_t *str1, const wchar_t *str2, size_t maxlen);

/**
 * Compare two null-terminated wide strings, case-insensitively.
 *
 * This will work with Unicode strings, using a technique called
 * "case-folding" to handle the vast majority of case-sensitive human
 * languages regardless of system locale. It can deal with expanding values: a
 * German Eszett character can compare against two ASCII 's' chars and be
 * considered a match, for example. A notable exception: it does not handle
 * the Turkish 'i' character; human language is complicated!
 *
 * Depending on your platform, "wchar_t" might be 2 bytes, and expected to be
 * UTF-16 encoded (like Windows), or 4 bytes in UTF-32 format. Since this
 * handles Unicode, it expects the string to be well-formed and not a
 * null-terminated string of arbitrary bytes. Characters that are not valid
 * UTF-16 (or UTF-32) are treated as Unicode character U+FFFD (REPLACEMENT
 * CHARACTER), which is to say two strings of random bits may turn out to
 * match if they convert to the same amount of replacement characters.
 *
 * \param str1 the first string to compare. NULL is not permitted!
 * \param str2 the second string to compare. NULL is not permitted!
 * \returns less than zero if str1 is "less than" str2, greater than zero if
 *          str1 is "greater than" str2, and zero if the strings match
 *          exactly.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_wcscasecmp(const wchar_t *str1, const wchar_t *str2);

/**
 * Compare two wide strings, case-insensitively, up to a number of wchar_t.
 *
 * This will work with Unicode strings, using a technique called
 * "case-folding" to handle the vast majority of case-sensitive human
 * languages regardless of system locale. It can deal with expanding values: a
 * German Eszett character can compare against two ASCII 's' chars and be
 * considered a match, for example. A notable exception: it does not handle
 * the Turkish 'i' character; human language is complicated!
 *
 * Depending on your platform, "wchar_t" might be 2 bytes, and expected to be
 * UTF-16 encoded (like Windows), or 4 bytes in UTF-32 format. Since this
 * handles Unicode, it expects the string to be well-formed and not a
 * null-terminated string of arbitrary bytes. Characters that are not valid
 * UTF-16 (or UTF-32) are treated as Unicode character U+FFFD (REPLACEMENT
 * CHARACTER), which is to say two strings of random bits may turn out to
 * match if they convert to the same amount of replacement characters.
 *
 * Note that while this function might deal with variable-sized characters,
 * `maxlen` specifies a _wchar_ limit! If the limit lands in the middle of a
 * multi-byte UTF-16 sequence, it may convert a portion of the final character
 * to one or more Unicode character U+FFFD (REPLACEMENT CHARACTER) so as not
 * to overflow a buffer.
 *
 * `maxlen` specifies a maximum number of wchar_t values to compare; if the
 * strings match to this number of wchar_t (or both have matched to a
 * null-terminator character before this number of bytes), they will be
 * considered equal.
 *
 * \param str1 the first string to compare. NULL is not permitted!
 * \param str2 the second string to compare. NULL is not permitted!
 * \param maxlen the maximum number of wchar_t values to compare.
 * \returns less than zero if str1 is "less than" str2, greater than zero if
 *          str1 is "greater than" str2, and zero if the strings match
 *          exactly.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_wcsncasecmp(const wchar_t *str1, const wchar_t *str2, size_t maxlen);

/**
 * Parse a `long` from a wide string.
 *
 * If `str` starts with whitespace, then those whitespace characters are
 * skipped before attempting to parse the number.
 *
 * If the parsed number does not fit inside a `long`, the result is clamped to
 * the minimum and maximum representable `long` values.
 *
 * \param str The null-terminated wide string to read. Must not be NULL.
 * \param endp If not NULL, the address of the first invalid wide character
 *             (i.e. the next character after the parsed number) will be
 *             written to this pointer.
 * \param base The base of the integer to read. Supported values are 0 and 2
 *             to 36 inclusive. If 0, the base will be inferred from the
 *             number's prefix (0x for hexadecimal, 0 for octal, decimal
 *             otherwise).
 * \returns the parsed `long`, or 0 if no number could be parsed.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_strtol
 */
extern SDL_DECLSPEC long SDLCALL SDL_wcstol(const wchar_t *str, wchar_t **endp, int base);

/**
 * This works exactly like strlen() but doesn't require access to a C runtime.
 *
 * Counts the bytes in `str`, excluding the null terminator.
 *
 * If you need the length of a UTF-8 string, consider using SDL_utf8strlen().
 *
 * \param str The null-terminated string to read. Must not be NULL.
 * \returns the length (in bytes, excluding the null terminator) of `src`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_strnlen
 * \sa SDL_utf8strlen
 * \sa SDL_utf8strnlen
 */
extern SDL_DECLSPEC size_t SDLCALL SDL_strlen(const char *str);

/**
 * This works exactly like strnlen() but doesn't require access to a C
 * runtime.
 *
 * Counts up to a maximum of `maxlen` bytes in `str`, excluding the null
 * terminator.
 *
 * If you need the length of a UTF-8 string, consider using SDL_utf8strnlen().
 *
 * \param str The null-terminated string to read. Must not be NULL.
 * \param maxlen The maximum amount of bytes to count.
 * \returns the length (in bytes, excluding the null terminator) of `src` but
 *          never more than `maxlen`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_strlen
 * \sa SDL_utf8strlen
 * \sa SDL_utf8strnlen
 */
extern SDL_DECLSPEC size_t SDLCALL SDL_strnlen(const char *str, size_t maxlen);

/**
 * Copy a string.
 *
 * This function copies up to `maxlen` - 1 characters from `src` to `dst`,
 * then appends a null terminator.
 *
 * If `maxlen` is 0, no characters are copied and no null terminator is
 * written.
 *
 * If you want to copy an UTF-8 string but need to ensure that multi-byte
 * sequences are not truncated, consider using SDL_utf8strlcpy().
 *
 * \param dst The destination buffer. Must not be NULL, and must not overlap
 *            with `src`.
 * \param src The null-terminated string to copy. Must not be NULL, and must
 *            not overlap with `dst`.
 * \param maxlen The length (in characters) of the destination buffer.
 * \returns the length (in characters, excluding the null terminator) of
 *          `src`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_strlcat
 * \sa SDL_utf8strlcpy
 */
extern SDL_DECLSPEC size_t SDLCALL SDL_strlcpy(SDL_OUT_Z_CAP(maxlen) char *dst, const char *src, size_t maxlen);

/**
 * Copy an UTF-8 string.
 *
 * This function copies up to `dst_bytes` - 1 bytes from `src` to `dst` while
 * also ensuring that the string written to `dst` does not end in a truncated
 * multi-byte sequence. Finally, it appends a null terminator.
 *
 * `src` and `dst` must not overlap.
 *
 * Note that unlike SDL_strlcpy(), this function returns the number of bytes
 * written, not the length of `src`.
 *
 * \param dst The destination buffer. Must not be NULL, and must not overlap
 *            with `src`.
 * \param src The null-terminated UTF-8 string to copy. Must not be NULL, and
 *            must not overlap with `dst`.
 * \param dst_bytes The length (in bytes) of the destination buffer. Must not
 *                  be 0.
 * \returns the number of bytes written, excluding the null terminator.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_strlcpy
 */
extern SDL_DECLSPEC size_t SDLCALL SDL_utf8strlcpy(SDL_OUT_Z_CAP(dst_bytes) char *dst, const char *src, size_t dst_bytes);

/**
 * Concatenate strings.
 *
 * This function appends up to `maxlen` - SDL_strlen(dst) - 1 characters from
 * `src` to the end of the string in `dst`, then appends a null terminator.
 *
 * `src` and `dst` must not overlap.
 *
 * If `maxlen` - SDL_strlen(dst) - 1 is less than or equal to 0, then `dst` is
 * unmodified.
 *
 * \param dst The destination buffer already containing the first
 *            null-terminated string. Must not be NULL and must not overlap
 *            with `src`.
 * \param src The second null-terminated string. Must not be NULL, and must
 *            not overlap with `dst`.
 * \param maxlen The length (in characters) of the destination buffer.
 * \returns the length (in characters, excluding the null terminator) of the
 *          string in `dst` plus the length of `src`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_strlcpy
 */
extern SDL_DECLSPEC size_t SDLCALL SDL_strlcat(SDL_INOUT_Z_CAP(maxlen) char *dst, const char *src, size_t maxlen);

/**
 * Allocate a copy of a string.
 *
 * This allocates enough space for a null-terminated copy of `str`, using
 * SDL_malloc, and then makes a copy of the string into this space.
 *
 * The returned string is owned by the caller, and should be passed to
 * SDL_free when no longer needed.
 *
 * \param str the string to copy.
 * \returns a pointer to the newly-allocated string.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC SDL_MALLOC char * SDLCALL SDL_strdup(const char *str);

/**
 * Allocate a copy of a string, up to n characters.
 *
 * This allocates enough space for a null-terminated copy of `str`, up to
 * `maxlen` bytes, using SDL_malloc, and then makes a copy of the string
 * into this space.
 *
 * If the string is longer than `maxlen` bytes, the returned string will
 * be `maxlen` bytes long, plus a null-terminator character that isn't
 * included in the count.
 *
 * The returned string is owned by the caller, and should be passed to
 * SDL_free when no longer needed.
 *
 * \param str the string to copy.
 * \param maxlen the maximum length of the copied string, not counting
 *        the null-terminator character.
 * \returns a pointer to the newly-allocated string.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC SDL_MALLOC char * SDLCALL SDL_strndup(const char *str, size_t maxlen);

/**
 * Reverse a string's contents.
 *
 * This reverses a null-terminated string in-place. Only the content of the
 * string is reversed; the null-terminator character remains at the end of the
 * reversed string.
 *
 * **WARNING**: This function reverses the _bytes_ of the string, not the
 * codepoints. If `str` is a UTF-8 string with Unicode codepoints > 127, this
 * will ruin the string data. You should only use this function on strings
 * that are completely comprised of low ASCII characters.
 *
 * \param str the string to reverse.
 * \returns `str`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC char * SDLCALL SDL_strrev(char *str);

/**
 * Convert a string to uppercase.
 *
 * **WARNING**: Regardless of system locale, this will only convert ASCII
 * values 'A' through 'Z' to uppercase.
 *
 * This function operates on a null-terminated string of bytes--even if it is
 * malformed UTF-8!--and converts ASCII characters 'a' through 'z' to their
 * uppercase equivalents in-place, returning the original `str` pointer.
 *
 * \param str the string to convert in-place. Can not be NULL.
 * \returns the `str` pointer passed into this function.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_strlwr
 */
extern SDL_DECLSPEC char * SDLCALL SDL_strupr(char *str);

/**
 * Convert a string to lowercase.
 *
 * **WARNING**: Regardless of system locale, this will only convert ASCII
 * values 'A' through 'Z' to lowercase.
 *
 * This function operates on a null-terminated string of bytes--even if it is
 * malformed UTF-8!--and converts ASCII characters 'A' through 'Z' to their
 * lowercase equivalents in-place, returning the original `str` pointer.
 *
 * \param str the string to convert in-place. Can not be NULL.
 * \returns the `str` pointer passed into this function.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_strupr
 */
extern SDL_DECLSPEC char * SDLCALL SDL_strlwr(char *str);

/**
 * Search a string for the first instance of a specific byte.
 *
 * The search ends once it finds the requested byte value, or a null
 * terminator byte to end the string.
 *
 * Note that this looks for _bytes_, not _characters_, so you cannot match
 * against a Unicode codepoint > 255, regardless of character encoding.
 *
 * \param str the string to search. Must not be NULL.
 * \param c the byte value to search for.
 * \returns a pointer to the first instance of `c` in the string, or NULL if
 *          not found.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC char * SDLCALL SDL_strchr(const char *str, int c);

/**
 * Search a string for the last instance of a specific byte.
 *
 * The search must go until it finds a null terminator byte to end the string.
 *
 * Note that this looks for _bytes_, not _characters_, so you cannot match
 * against a Unicode codepoint > 255, regardless of character encoding.
 *
 * \param str the string to search. Must not be NULL.
 * \param c the byte value to search for.
 * \returns a pointer to the last instance of `c` in the string, or NULL if
 *          not found.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC char * SDLCALL SDL_strrchr(const char *str, int c);

/**
 * Search a string for the first instance of a specific substring.
 *
 * The search ends once it finds the requested substring, or a null terminator
 * byte to end the string.
 *
 * Note that this looks for strings of _bytes_, not _characters_, so it's
 * legal to search for malformed and incomplete UTF-8 sequences.
 *
 * \param haystack the string to search. Must not be NULL.
 * \param needle the string to search for. Must not be NULL.
 * \returns a pointer to the first instance of `needle` in the string, or NULL
 *          if not found.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC char * SDLCALL SDL_strstr(const char *haystack, const char *needle);

/**
 * Search a string, up to n bytes, for the first instance of a specific
 * substring.
 *
 * The search ends once it finds the requested substring, or a null terminator
 * byte to end the string, or `maxlen` bytes have been examined. It is
 * possible to use this function on a string without a null terminator.
 *
 * Note that this looks for strings of _bytes_, not _characters_, so it's
 * legal to search for malformed and incomplete UTF-8 sequences.
 *
 * \param haystack the string to search. Must not be NULL.
 * \param needle the string to search for. Must not be NULL.
 * \param maxlen the maximum number of bytes to search in `haystack`.
 * \returns a pointer to the first instance of `needle` in the string, or NULL
 *          if not found.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC char * SDLCALL SDL_strnstr(const char *haystack, const char *needle, size_t maxlen);

/**
 * Search a UTF-8 string for the first instance of a specific substring,
 * case-insensitively.
 *
 * This will work with Unicode strings, using a technique called
 * "case-folding" to handle the vast majority of case-sensitive human
 * languages regardless of system locale. It can deal with expanding values: a
 * German Eszett character can compare against two ASCII 's' chars and be
 * considered a match, for example. A notable exception: it does not handle
 * the Turkish 'i' character; human language is complicated!
 *
 * Since this handles Unicode, it expects the strings to be well-formed UTF-8
 * and not a null-terminated string of arbitrary bytes. Bytes that are not
 * valid UTF-8 are treated as Unicode character U+FFFD (REPLACEMENT
 * CHARACTER), which is to say two strings of random bits may turn out to
 * match if they convert to the same amount of replacement characters.
 *
 * \param haystack the string to search. Must not be NULL.
 * \param needle the string to search for. Must not be NULL.
 * \returns a pointer to the first instance of `needle` in the string, or NULL
 *          if not found.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC char * SDLCALL SDL_strcasestr(const char *haystack, const char *needle);

/**
 * This works exactly like strtok_r() but doesn't require access to a C
 * runtime.
 *
 * Break a string up into a series of tokens.
 *
 * To start tokenizing a new string, `str` should be the non-NULL address of
 * the string to start tokenizing. Future calls to get the next token from the
 * same string should specify a NULL.
 *
 * Note that this function will overwrite pieces of `str` with null chars to
 * split it into tokens. This function cannot be used with const/read-only
 * strings!
 *
 * `saveptr` just needs to point to a `char *` that can be overwritten; SDL
 * will use this to save tokenizing state between calls. It is initialized if
 * `str` is non-NULL, and used to resume tokenizing when `str` is NULL.
 *
 * \param str the string to tokenize, or NULL to continue tokenizing.
 * \param delim the delimiter string that separates tokens.
 * \param saveptr pointer to a char *, used for ongoing state.
 * \returns A pointer to the next token, or NULL if no tokens remain.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC char * SDLCALL SDL_strtok_r(char *str, const char *delim, char **saveptr);

/**
 * Count the number of codepoints in a UTF-8 string.
 *
 * Counts the _codepoints_, not _bytes_, in `str`, excluding the null
 * terminator.
 *
 * If you need to count the bytes in a string instead, consider using
 * SDL_strlen().
 *
 * Since this handles Unicode, it expects the strings to be well-formed UTF-8
 * and not a null-terminated string of arbitrary bytes. Bytes that are not
 * valid UTF-8 are treated as Unicode character U+FFFD (REPLACEMENT
 * CHARACTER), so a malformed or incomplete UTF-8 sequence might increase the
 * count by several replacement characters.
 *
 * \param str The null-terminated UTF-8 string to read. Must not be NULL.
 * \returns The length (in codepoints, excluding the null terminator) of
 *          `src`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_utf8strnlen
 * \sa SDL_strlen
 */
extern SDL_DECLSPEC size_t SDLCALL SDL_utf8strlen(const char *str);

/**
 * Count the number of codepoints in a UTF-8 string, up to n bytes.
 *
 * Counts the _codepoints_, not _bytes_, in `str`, excluding the null
 * terminator.
 *
 * If you need to count the bytes in a string instead, consider using
 * SDL_strnlen().
 *
 * The counting stops at `bytes` bytes (not codepoints!). This seems
 * counterintuitive, but makes it easy to express the total size of the
 * string's buffer.
 *
 * Since this handles Unicode, it expects the strings to be well-formed UTF-8
 * and not a null-terminated string of arbitrary bytes. Bytes that are not
 * valid UTF-8 are treated as Unicode character U+FFFD (REPLACEMENT
 * CHARACTER), so a malformed or incomplete UTF-8 sequence might increase the
 * count by several replacement characters.
 *
 * \param str The null-terminated UTF-8 string to read. Must not be NULL.
 * \param bytes The maximum amount of bytes to count.
 * \returns The length (in codepoints, excluding the null terminator) of `src`
 *          but never more than `maxlen`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_utf8strlen
 * \sa SDL_strnlen
 */
extern SDL_DECLSPEC size_t SDLCALL SDL_utf8strnlen(const char *str, size_t bytes);

/**
 * Convert an integer into a string.
 *
 * This requires a radix to specified for string format. Specifying 10
 * produces a decimal number, 16 hexidecimal, etc. Must be in the range of 2
 * to 36.
 *
 * Note that this function will overflow a buffer if `str` is not large enough
 * to hold the output! It may be safer to use SDL_snprintf to clamp output, or
 * SDL_asprintf to allocate a buffer. Otherwise, it doesn't hurt to allocate
 * much more space than you expect to use (and don't forget possible negative
 * signs, null terminator bytes, etc).
 *
 * \param value the integer to convert.
 * \param str the buffer to write the string into.
 * \param radix the radix to use for string generation.
 * \returns `str`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_uitoa
 * \sa SDL_ltoa
 * \sa SDL_lltoa
 */
extern SDL_DECLSPEC char * SDLCALL SDL_itoa(int value, char *str, int radix);

/**
 * Convert an unsigned integer into a string.
 *
 * This requires a radix to specified for string format. Specifying 10
 * produces a decimal number, 16 hexidecimal, etc. Must be in the range of 2
 * to 36.
 *
 * Note that this function will overflow a buffer if `str` is not large enough
 * to hold the output! It may be safer to use SDL_snprintf to clamp output, or
 * SDL_asprintf to allocate a buffer. Otherwise, it doesn't hurt to allocate
 * much more space than you expect to use (and don't forget null terminator
 * bytes, etc).
 *
 * \param value the unsigned integer to convert.
 * \param str the buffer to write the string into.
 * \param radix the radix to use for string generation.
 * \returns `str`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_itoa
 * \sa SDL_ultoa
 * \sa SDL_ulltoa
 */
extern SDL_DECLSPEC char * SDLCALL SDL_uitoa(unsigned int value, char *str, int radix);

/**
 * Convert a long integer into a string.
 *
 * This requires a radix to specified for string format. Specifying 10
 * produces a decimal number, 16 hexidecimal, etc. Must be in the range of 2
 * to 36.
 *
 * Note that this function will overflow a buffer if `str` is not large enough
 * to hold the output! It may be safer to use SDL_snprintf to clamp output, or
 * SDL_asprintf to allocate a buffer. Otherwise, it doesn't hurt to allocate
 * much more space than you expect to use (and don't forget possible negative
 * signs, null terminator bytes, etc).
 *
 * \param value the long integer to convert.
 * \param str the buffer to write the string into.
 * \param radix the radix to use for string generation.
 * \returns `str`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_ultoa
 * \sa SDL_itoa
 * \sa SDL_lltoa
 */
extern SDL_DECLSPEC char * SDLCALL SDL_ltoa(long value, char *str, int radix);

/**
 * Convert an unsigned long integer into a string.
 *
 * This requires a radix to specified for string format. Specifying 10
 * produces a decimal number, 16 hexidecimal, etc. Must be in the range of 2
 * to 36.
 *
 * Note that this function will overflow a buffer if `str` is not large enough
 * to hold the output! It may be safer to use SDL_snprintf to clamp output, or
 * SDL_asprintf to allocate a buffer. Otherwise, it doesn't hurt to allocate
 * much more space than you expect to use (and don't forget null terminator
 * bytes, etc).
 *
 * \param value the unsigned long integer to convert.
 * \param str the buffer to write the string into.
 * \param radix the radix to use for string generation.
 * \returns `str`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_ltoa
 * \sa SDL_uitoa
 * \sa SDL_ulltoa
 */
extern SDL_DECLSPEC char * SDLCALL SDL_ultoa(unsigned long value, char *str, int radix);

/**
 * Convert a long long integer into a string.
 *
 * This requires a radix to specified for string format. Specifying 10
 * produces a decimal number, 16 hexidecimal, etc. Must be in the range of 2
 * to 36.
 *
 * Note that this function will overflow a buffer if `str` is not large enough
 * to hold the output! It may be safer to use SDL_snprintf to clamp output, or
 * SDL_asprintf to allocate a buffer. Otherwise, it doesn't hurt to allocate
 * much more space than you expect to use (and don't forget possible negative
 * signs, null terminator bytes, etc).
 *
 * \param value the long long integer to convert.
 * \param str the buffer to write the string into.
 * \param radix the radix to use for string generation.
 * \returns `str`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_ulltoa
 * \sa SDL_itoa
 * \sa SDL_ltoa
 */
extern SDL_DECLSPEC char * SDLCALL SDL_lltoa(long long value, char *str, int radix);

/**
 * Convert an unsigned long long integer into a string.
 *
 * This requires a radix to specified for string format. Specifying 10
 * produces a decimal number, 16 hexidecimal, etc. Must be in the range of 2
 * to 36.
 *
 * Note that this function will overflow a buffer if `str` is not large enough
 * to hold the output! It may be safer to use SDL_snprintf to clamp output, or
 * SDL_asprintf to allocate a buffer. Otherwise, it doesn't hurt to allocate
 * much more space than you expect to use (and don't forget null terminator
 * bytes, etc).
 *
 * \param value the unsigned long long integer to convert.
 * \param str the buffer to write the string into.
 * \param radix the radix to use for string generation.
 * \returns `str`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_lltoa
 * \sa SDL_uitoa
 * \sa SDL_ultoa
 */
extern SDL_DECLSPEC char * SDLCALL SDL_ulltoa(unsigned long long value, char *str, int radix);

/**
 * Parse an `int` from a string.
 *
 * The result of calling `SDL_atoi(str)` is equivalent to
 * `(int)SDL_strtol(str, NULL, 10)`.
 *
 * \param str The null-terminated string to read. Must not be NULL.
 * \returns the parsed `int`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_atof
 * \sa SDL_strtol
 * \sa SDL_strtoul
 * \sa SDL_strtoll
 * \sa SDL_strtoull
 * \sa SDL_strtod
 * \sa SDL_itoa
 */
extern SDL_DECLSPEC int SDLCALL SDL_atoi(const char *str);

/**
 * Parse a `double` from a string.
 *
 * The result of calling `SDL_atof(str)` is equivalent to `SDL_strtod(str,
 * NULL)`.
 *
 * \param str The null-terminated string to read. Must not be NULL.
 * \returns the parsed `double`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_atoi
 * \sa SDL_strtol
 * \sa SDL_strtoul
 * \sa SDL_strtoll
 * \sa SDL_strtoull
 * \sa SDL_strtod
 */
extern SDL_DECLSPEC double SDLCALL SDL_atof(const char *str);

/**
 * Parse a `long` from a string.
 *
 * If `str` starts with whitespace, then those whitespace characters are
 * skipped before attempting to parse the number.
 *
 * If the parsed number does not fit inside a `long`, the result is clamped to
 * the minimum and maximum representable `long` values.
 *
 * \param str The null-terminated string to read. Must not be NULL.
 * \param endp If not NULL, the address of the first invalid character (i.e.
 *             the next character after the parsed number) will be written to
 *             this pointer.
 * \param base The base of the integer to read. Supported values are 0 and 2
 *             to 36 inclusive. If 0, the base will be inferred from the
 *             number's prefix (0x for hexadecimal, 0 for octal, decimal
 *             otherwise).
 * \returns the parsed `long`, or 0 if no number could be parsed.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_atoi
 * \sa SDL_atof
 * \sa SDL_strtoul
 * \sa SDL_strtoll
 * \sa SDL_strtoull
 * \sa SDL_strtod
 * \sa SDL_ltoa
 * \sa SDL_wcstol
 */
extern SDL_DECLSPEC long SDLCALL SDL_strtol(const char *str, char **endp, int base);

/**
 * Parse an `unsigned long` from a string.
 *
 * If `str` starts with whitespace, then those whitespace characters are
 * skipped before attempting to parse the number.
 *
 * If the parsed number does not fit inside an `unsigned long`, the result is
 * clamped to the maximum representable `unsigned long` value.
 *
 * \param str The null-terminated string to read. Must not be NULL.
 * \param endp If not NULL, the address of the first invalid character (i.e.
 *             the next character after the parsed number) will be written to
 *             this pointer.
 * \param base The base of the integer to read. Supported values are 0 and 2
 *             to 36 inclusive. If 0, the base will be inferred from the
 *             number's prefix (0x for hexadecimal, 0 for octal, decimal
 *             otherwise).
 * \returns the parsed `unsigned long`, or 0 if no number could be parsed.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_atoi
 * \sa SDL_atof
 * \sa SDL_strtol
 * \sa SDL_strtoll
 * \sa SDL_strtoull
 * \sa SDL_strtod
 * \sa SDL_ultoa
 */
extern SDL_DECLSPEC unsigned long SDLCALL SDL_strtoul(const char *str, char **endp, int base);

/**
 * Parse a `long long` from a string.
 *
 * If `str` starts with whitespace, then those whitespace characters are
 * skipped before attempting to parse the number.
 *
 * If the parsed number does not fit inside a `long long`, the result is
 * clamped to the minimum and maximum representable `long long` values.
 *
 * \param str The null-terminated string to read. Must not be NULL.
 * \param endp If not NULL, the address of the first invalid character (i.e.
 *             the next character after the parsed number) will be written to
 *             this pointer.
 * \param base The base of the integer to read. Supported values are 0 and 2
 *             to 36 inclusive. If 0, the base will be inferred from the
 *             number's prefix (0x for hexadecimal, 0 for octal, decimal
 *             otherwise).
 * \returns the parsed `long long`, or 0 if no number could be parsed.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_atoi
 * \sa SDL_atof
 * \sa SDL_strtol
 * \sa SDL_strtoul
 * \sa SDL_strtoull
 * \sa SDL_strtod
 * \sa SDL_lltoa
 */
extern SDL_DECLSPEC long long SDLCALL SDL_strtoll(const char *str, char **endp, int base);

/**
 * Parse an `unsigned long long` from a string.
 *
 * If `str` starts with whitespace, then those whitespace characters are
 * skipped before attempting to parse the number.
 *
 * If the parsed number does not fit inside an `unsigned long long`, the
 * result is clamped to the maximum representable `unsigned long long` value.
 *
 * \param str The null-terminated string to read. Must not be NULL.
 * \param endp If not NULL, the address of the first invalid character (i.e.
 *             the next character after the parsed number) will be written to
 *             this pointer.
 * \param base The base of the integer to read. Supported values are 0 and 2
 *             to 36 inclusive. If 0, the base will be inferred from the
 *             number's prefix (0x for hexadecimal, 0 for octal, decimal
 *             otherwise).
 * \returns the parsed `unsigned long long`, or 0 if no number could be
 *          parsed.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_atoi
 * \sa SDL_atof
 * \sa SDL_strtol
 * \sa SDL_strtoll
 * \sa SDL_strtoul
 * \sa SDL_strtod
 * \sa SDL_ulltoa
 */
extern SDL_DECLSPEC unsigned long long SDLCALL SDL_strtoull(const char *str, char **endp, int base);

/**
 * Parse a `double` from a string.
 *
 * This function makes fewer guarantees than the C runtime `strtod`:
 *
 * - Only decimal notation is guaranteed to be supported. The handling of
 *   scientific and hexadecimal notation is unspecified.
 * - Whether or not INF and NAN can be parsed is unspecified.
 * - The precision of the result is unspecified.
 *
 * \param str the null-terminated string to read. Must not be NULL.
 * \param endp if not NULL, the address of the first invalid character (i.e.
 *             the next character after the parsed number) will be written to
 *             this pointer.
 * \returns the parsed `double`, or 0 if no number could be parsed.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_atoi
 * \sa SDL_atof
 * \sa SDL_strtol
 * \sa SDL_strtoll
 * \sa SDL_strtoul
 * \sa SDL_strtoull
 */
extern SDL_DECLSPEC double SDLCALL SDL_strtod(const char *str, char **endp);

/**
 * Compare two null-terminated UTF-8 strings.
 *
 * Due to the nature of UTF-8 encoding, this will work with Unicode strings,
 * since effectively this function just compares bytes until it hits a
 * null-terminating character. Also due to the nature of UTF-8, this can be
 * used with SDL_qsort() to put strings in (roughly) alphabetical order.
 *
 * \param str1 the first string to compare. NULL is not permitted!
 * \param str2 the second string to compare. NULL is not permitted!
 * \returns less than zero if str1 is "less than" str2, greater than zero if
 *          str1 is "greater than" str2, and zero if the strings match
 *          exactly.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_strcmp(const char *str1, const char *str2);

/**
 * Compare two UTF-8 strings up to a number of bytes.
 *
 * Due to the nature of UTF-8 encoding, this will work with Unicode strings,
 * since effectively this function just compares bytes until it hits a
 * null-terminating character. Also due to the nature of UTF-8, this can be
 * used with SDL_qsort() to put strings in (roughly) alphabetical order.
 *
 * Note that while this function is intended to be used with UTF-8, it is
 * doing a bytewise comparison, and `maxlen` specifies a _byte_ limit! If the
 * limit lands in the middle of a multi-byte UTF-8 sequence, it will only
 * compare a portion of the final character.
 *
 * `maxlen` specifies a maximum number of bytes to compare; if the strings
 * match to this number of bytes (or both have matched to a null-terminator
 * character before this number of bytes), they will be considered equal.
 *
 * \param str1 the first string to compare. NULL is not permitted!
 * \param str2 the second string to compare. NULL is not permitted!
 * \param maxlen the maximum number of _bytes_ to compare.
 * \returns less than zero if str1 is "less than" str2, greater than zero if
 *          str1 is "greater than" str2, and zero if the strings match
 *          exactly.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_strncmp(const char *str1, const char *str2, size_t maxlen);

/**
 * Compare two null-terminated UTF-8 strings, case-insensitively.
 *
 * This will work with Unicode strings, using a technique called
 * "case-folding" to handle the vast majority of case-sensitive human
 * languages regardless of system locale. It can deal with expanding values: a
 * German Eszett character can compare against two ASCII 's' chars and be
 * considered a match, for example. A notable exception: it does not handle
 * the Turkish 'i' character; human language is complicated!
 *
 * Since this handles Unicode, it expects the string to be well-formed UTF-8
 * and not a null-terminated string of arbitrary bytes. Bytes that are not
 * valid UTF-8 are treated as Unicode character U+FFFD (REPLACEMENT
 * CHARACTER), which is to say two strings of random bits may turn out to
 * match if they convert to the same amount of replacement characters.
 *
 * \param str1 the first string to compare. NULL is not permitted!
 * \param str2 the second string to compare. NULL is not permitted!
 * \returns less than zero if str1 is "less than" str2, greater than zero if
 *          str1 is "greater than" str2, and zero if the strings match
 *          exactly.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_strcasecmp(const char *str1, const char *str2);


/**
 * Compare two UTF-8 strings, case-insensitively, up to a number of bytes.
 *
 * This will work with Unicode strings, using a technique called
 * "case-folding" to handle the vast majority of case-sensitive human
 * languages regardless of system locale. It can deal with expanding values: a
 * German Eszett character can compare against two ASCII 's' chars and be
 * considered a match, for example. A notable exception: it does not handle
 * the Turkish 'i' character; human language is complicated!
 *
 * Since this handles Unicode, it expects the string to be well-formed UTF-8
 * and not a null-terminated string of arbitrary bytes. Bytes that are not
 * valid UTF-8 are treated as Unicode character U+FFFD (REPLACEMENT
 * CHARACTER), which is to say two strings of random bits may turn out to
 * match if they convert to the same amount of replacement characters.
 *
 * Note that while this function is intended to be used with UTF-8, `maxlen`
 * specifies a _byte_ limit! If the limit lands in the middle of a multi-byte
 * UTF-8 sequence, it may convert a portion of the final character to one or
 * more Unicode character U+FFFD (REPLACEMENT CHARACTER) so as not to overflow
 * a buffer.
 *
 * `maxlen` specifies a maximum number of bytes to compare; if the strings
 * match to this number of bytes (or both have matched to a null-terminator
 * character before this number of bytes), they will be considered equal.
 *
 * \param str1 the first string to compare. NULL is not permitted!
 * \param str2 the second string to compare. NULL is not permitted!
 * \param maxlen the maximum number of bytes to compare.
 * \returns less than zero if str1 is "less than" str2, greater than zero if
 *          str1 is "greater than" str2, and zero if the strings match
 *          exactly.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_strncasecmp(const char *str1, const char *str2, size_t maxlen);

/**
 * Searches a string for the first occurence of any character contained in a
 * breakset, and returns a pointer from the string to that character.
 *
 * \param str The null-terminated string to be searched. Must not be NULL, and
 *            must not overlap with `breakset`.
 * \param breakset A null-terminated string containing the list of characters
 *                 to look for. Must not be NULL, and must not overlap with
 *                 `str`.
 * \returns A pointer to the location, in str, of the first occurence of a
 *          character present in the breakset, or NULL if none is found.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC char * SDLCALL SDL_strpbrk(const char *str, const char *breakset);

/**
 * The Unicode REPLACEMENT CHARACTER codepoint.
 *
 * SDL_StepUTF8() and SDL_StepBackUTF8() report this codepoint when they
 * encounter a UTF-8 string with encoding errors.
 *
 * This tends to render as something like a question mark in most places.
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_StepBackUTF8
 * \sa SDL_StepUTF8
 */
#define SDL_INVALID_UNICODE_CODEPOINT 0xFFFD

/**
 * Decode a UTF-8 string, one Unicode codepoint at a time.
 *
 * This will return the first Unicode codepoint in the UTF-8 encoded string in
 * `*pstr`, and then advance `*pstr` past any consumed bytes before returning.
 *
 * It will not access more than `*pslen` bytes from the string. `*pslen` will
 * be adjusted, as well, subtracting the number of bytes consumed.
 *
 * `pslen` is allowed to be NULL, in which case the string _must_ be
 * NULL-terminated, as the function will blindly read until it sees the NULL
 * char.
 *
 * if `*pslen` is zero, it assumes the end of string is reached and returns a
 * zero codepoint regardless of the contents of the string buffer.
 *
 * If the resulting codepoint is zero (a NULL terminator), or `*pslen` is
 * zero, it will not advance `*pstr` or `*pslen` at all.
 *
 * Generally this function is called in a loop until it returns zero,
 * adjusting its parameters each iteration.
 *
 * If an invalid UTF-8 sequence is encountered, this function returns
 * SDL_INVALID_UNICODE_CODEPOINT and advances the string/length by one byte
 * (which is to say, a multibyte sequence might produce several
 * SDL_INVALID_UNICODE_CODEPOINT returns before it syncs to the next valid
 * UTF-8 sequence).
 *
 * Several things can generate invalid UTF-8 sequences, including overlong
 * encodings, the use of UTF-16 surrogate values, and truncated data. Please
 * refer to
 * [RFC3629](https://www.ietf.org/rfc/rfc3629.txt)
 * for details.
 *
 * \param pstr a pointer to a UTF-8 string pointer to be read and adjusted.
 * \param pslen a pointer to the number of bytes in the string, to be read and
 *              adjusted. NULL is allowed.
 * \returns the first Unicode codepoint in the string.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC Uint32 SDLCALL SDL_StepUTF8(const char **pstr, size_t *pslen);

/**
 * Decode a UTF-8 string in reverse, one Unicode codepoint at a time.
 *
 * This will go to the start of the previous Unicode codepoint in the string,
 * move `*pstr` to that location and return that codepoint.
 *
 * If `*pstr` is already at the start of the string), it will not advance
 * `*pstr` at all.
 *
 * Generally this function is called in a loop until it returns zero,
 * adjusting its parameter each iteration.
 *
 * If an invalid UTF-8 sequence is encountered, this function returns
 * SDL_INVALID_UNICODE_CODEPOINT.
 *
 * Several things can generate invalid UTF-8 sequences, including overlong
 * encodings, the use of UTF-16 surrogate values, and truncated data. Please
 * refer to
 * [RFC3629](https://www.ietf.org/rfc/rfc3629.txt)
 * for details.
 *
 * \param start a pointer to the beginning of the UTF-8 string.
 * \param pstr a pointer to a UTF-8 string pointer to be read and adjusted.
 * \returns the previous Unicode codepoint in the string.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.6.
 */
extern SDL_DECLSPEC Uint32 SDLCALL SDL_StepBackUTF8(const char *start, const char **pstr);

/**
 * Convert a single Unicode codepoint to UTF-8.
 *
 * The buffer pointed to by `dst` must be at least 4 bytes long, as this
 * function may generate between 1 and 4 bytes of output.
 *
 * This function returns the first byte _after_ the newly-written UTF-8
 * sequence, which is useful for encoding multiple codepoints in a loop, or
 * knowing where to write a NULL-terminator character to end the string (in
 * either case, plan to have a buffer of _more_ than 4 bytes!).
 *
 * If `codepoint` is an invalid value (outside the Unicode range, or a UTF-16
 * surrogate value, etc), this will use U+FFFD (REPLACEMENT CHARACTER) for the
 * codepoint instead, and not set an error.
 *
 * If `dst` is NULL, this returns NULL immediately without writing to the
 * pointer and without setting an error.
 *
 * \param codepoint a Unicode codepoint to convert to UTF-8.
 * \param dst the location to write the encoded UTF-8. Must point to at least
 *            4 bytes!
 * \returns the first byte past the newly-written UTF-8 sequence.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC char * SDLCALL SDL_UCS4ToUTF8(Uint32 codepoint, char *dst);

/**
 * This works exactly like sscanf() but doesn't require access to a C runtime.
 *
 * Scan a string, matching a format string, converting each '%' item and
 * storing it to pointers provided through variable arguments.
 *
 * \param text the string to scan. Must not be NULL.
 * \param fmt a printf-style format string. Must not be NULL.
 * \param ... a list of pointers to values to be filled in with scanned items.
 * \returns the number of items that matched the format string.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_sscanf(const char *text, SDL_SCANF_FORMAT_STRING const char *fmt, ...) SDL_SCANF_VARARG_FUNC(2);

/**
 * This works exactly like vsscanf() but doesn't require access to a C runtime.
 *
 * Functions identically to SDL_sscanf(), except it takes a `va_list`
 * instead of using `...` variable arguments.
 *
 * \param text the string to scan. Must not be NULL.
 * \param fmt a printf-style format string. Must not be NULL.
 * \param ap a `va_list` of pointers to values to be filled in with scanned items.
 * \returns the number of items that matched the format string.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_vsscanf(const char *text, SDL_SCANF_FORMAT_STRING const char *fmt, va_list ap) SDL_SCANF_VARARG_FUNCV(2);

/**
 * This works exactly like snprintf() but doesn't require access to a C runtime.
 *
 * Format a string of up to `maxlen`-1 bytes, converting each '%' item with
 * values provided through variable arguments.
 *
 * While some C runtimes differ on how to deal with too-large strings,
 * this function null-terminates the output, by treating the null-terminator
 * as part of the `maxlen` count. Note that if `maxlen` is zero, however, no
 * bytes will be written at all.
 *
 * This function returns the number of _bytes_ (not _characters_) that should
 * be written, excluding the null-terminator character. If this returns a
 * number >= `maxlen`, it means the output string was truncated. A negative
 * return value means an error occurred.
 *
 * Referencing the output string's pointer with a format item is undefined
 * behavior.
 *
 * \param text the buffer to write the string into. Must not be NULL.
 * \param maxlen the maximum bytes to write, including the null-terminator.
 * \param fmt a printf-style format string. Must not be NULL.
 * \param ... a list of values to be used with the format string.
 * \returns the number of bytes that should be written, not counting the
 *          null-terminator char, or a negative value on error.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_snprintf(SDL_OUT_Z_CAP(maxlen) char *text, size_t maxlen, SDL_PRINTF_FORMAT_STRING const char *fmt, ...) SDL_PRINTF_VARARG_FUNC(3);

/**
 * This works exactly like swprintf() but doesn't require access to a C runtime.
 *
 * Format a wide string of up to `maxlen`-1 wchar_t values, converting each '%'
 * item with values provided through variable arguments.
 *
 * While some C runtimes differ on how to deal with too-large strings,
 * this function null-terminates the output, by treating the null-terminator
 * as part of the `maxlen` count. Note that if `maxlen` is zero, however, no
 * wide characters will be written at all.
 *
 * This function returns the number of _wide characters_ (not _codepoints_)
 * that should be written, excluding the null-terminator character. If this
 * returns a number >= `maxlen`, it means the output string was truncated. A
 * negative return value means an error occurred.
 *
 * Referencing the output string's pointer with a format item is undefined
 * behavior.
 *
 * \param text the buffer to write the wide string into. Must not be NULL.
 * \param maxlen the maximum wchar_t values to write, including the null-terminator.
 * \param fmt a printf-style format string. Must not be NULL.
 * \param ... a list of values to be used with the format string.
 * \returns the number of wide characters that should be written, not counting
 *          the null-terminator char, or a negative value on error.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_swprintf(SDL_OUT_Z_CAP(maxlen) wchar_t *text, size_t maxlen, SDL_PRINTF_FORMAT_STRING const wchar_t *fmt, ...) SDL_WPRINTF_VARARG_FUNC(3);

/**
 * This works exactly like vsnprintf() but doesn't require access to a C runtime.
 *
 * Functions identically to SDL_snprintf(), except it takes a `va_list`
 * instead of using `...` variable arguments.
 *
 * \param text the buffer to write the string into. Must not be NULL.
 * \param maxlen the maximum bytes to write, including the null-terminator.
 * \param fmt a printf-style format string. Must not be NULL.
 * \param ap a `va_list` values to be used with the format string.
 * \returns the number of bytes that should be written, not counting the
 *          null-terminator char, or a negative value on error.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_vsnprintf(SDL_OUT_Z_CAP(maxlen) char *text, size_t maxlen, SDL_PRINTF_FORMAT_STRING const char *fmt, va_list ap) SDL_PRINTF_VARARG_FUNCV(3);

/**
 * This works exactly like vswprintf() but doesn't require access to a C runtime.
 *
 * Functions identically to SDL_swprintf(), except it takes a `va_list`
 * instead of using `...` variable arguments.
 *
 * \param text the buffer to write the string into. Must not be NULL.
 * \param maxlen the maximum wide characters to write, including the null-terminator.
 * \param fmt a printf-style format wide string. Must not be NULL.
 * \param ap a `va_list` values to be used with the format string.
 * \returns the number of wide characters that should be written, not counting
 *          the null-terminator char, or a negative value on error.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_vswprintf(SDL_OUT_Z_CAP(maxlen) wchar_t *text, size_t maxlen, SDL_PRINTF_FORMAT_STRING const wchar_t *fmt, va_list ap) SDL_WPRINTF_VARARG_FUNCV(3);

/**
 * This works exactly like asprintf() but doesn't require access to a C runtime.
 *
 * Functions identically to SDL_snprintf(), except it allocates a buffer large
 * enough to hold the output string on behalf of the caller.
 *
 * On success, this function returns the number of bytes (not characters)
 * comprising the output string, not counting the null-terminator character,
 * and sets `*strp` to the newly-allocated string.
 *
 * On error, this function returns a negative number, and the value of `*strp`
 * is undefined.
 *
 * The returned string is owned by the caller, and should be passed to
 * SDL_free when no longer needed.
 *
 * \param strp on output, is set to the new string. Must not be NULL.
 * \param fmt a printf-style format string. Must not be NULL.
 * \param ... a list of values to be used with the format string.
 * \returns the number of bytes in the newly-allocated string, not counting
 *          the null-terminator char, or a negative value on error.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_asprintf(char **strp, SDL_PRINTF_FORMAT_STRING const char *fmt, ...) SDL_PRINTF_VARARG_FUNC(2);

/**
 * This works exactly like vasprintf() but doesn't require access to a C runtime.
 *
 * Functions identically to SDL_asprintf(), except it takes a `va_list`
 * instead of using `...` variable arguments.
 *
 * \param strp on output, is set to the new string. Must not be NULL.
 * \param fmt a printf-style format string. Must not be NULL.
 * \param ap a `va_list` values to be used with the format string.
 * \returns the number of bytes in the newly-allocated string, not counting
 *          the null-terminator char, or a negative value on error.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
extern SDL_DECLSPEC int SDLCALL SDL_vasprintf(char **strp, SDL_PRINTF_FORMAT_STRING const char *fmt, va_list ap) SDL_PRINTF_VARARG_FUNCV(2);

/**
 * Seeds the pseudo-random number generator.
 *
 * Reusing the seed number will cause SDL_rand_*() to repeat the same stream
 * of 'random' numbers.
 *
 * \param seed the value to use as a random number seed, or 0 to use
 *             SDL_GetPerformanceCounter().
 *
 * \threadsafety This should be called on the same thread that calls
 *               SDL_rand*()
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_rand
 * \sa SDL_rand_bits
 * \sa SDL_randf
 */
extern SDL_DECLSPEC void SDLCALL SDL_srand(Uint64 seed);

/**
 * Generate a pseudo-random number less than n for positive n
 *
 * The method used is faster and of better quality than `rand() % n`. Odds are
 * roughly 99.9% even for n = 1 million. Evenness is better for smaller n, and
 * much worse as n gets bigger.
 *
 * Example: to simulate a d6 use `SDL_rand(6) + 1` The +1 converts 0..5 to
 * 1..6
 *
 * If you want to generate a pseudo-random number in the full range of Sint32,
 * you should use: (Sint32)SDL_rand_bits()
 *
 * If you want reproducible output, be sure to initialize with SDL_srand()
 * first.
 *
 * There are no guarantees as to the quality of the random sequence produced,
 * and this should not be used for security (cryptography, passwords) or where
 * money is on the line (loot-boxes, casinos). There are many random number
 * libraries available with different characteristics and you should pick one
 * of those to meet any serious needs.
 *
 * \param n the number of possible outcomes. n must be positive.
 * \returns a random value in the range of [0 .. n-1].
 *
 * \threadsafety All calls should be made from a single thread
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_srand
 * \sa SDL_randf
 */
extern SDL_DECLSPEC Sint32 SDLCALL SDL_rand(Sint32 n);

/**
 * Generate a uniform pseudo-random floating point number less than 1.0
 *
 * If you want reproducible output, be sure to initialize with SDL_srand()
 * first.
 *
 * There are no guarantees as to the quality of the random sequence produced,
 * and this should not be used for security (cryptography, passwords) or where
 * money is on the line (loot-boxes, casinos). There are many random number
 * libraries available with different characteristics and you should pick one
 * of those to meet any serious needs.
 *
 * \returns a random value in the range of [0.0, 1.0).
 *
 * \threadsafety All calls should be made from a single thread
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_srand
 * \sa SDL_rand
 */
extern SDL_DECLSPEC float SDLCALL SDL_randf(void);

/**
 * Generate 32 pseudo-random bits.
 *
 * You likely want to use SDL_rand() to get a psuedo-random number instead.
 *
 * There are no guarantees as to the quality of the random sequence produced,
 * and this should not be used for security (cryptography, passwords) or where
 * money is on the line (loot-boxes, casinos). There are many random number
 * libraries available with different characteristics and you should pick one
 * of those to meet any serious needs.
 *
 * \returns a random value in the range of [0-SDL_MAX_UINT32].
 *
 * \threadsafety All calls should be made from a single thread
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_rand
 * \sa SDL_randf
 * \sa SDL_srand
 */
extern SDL_DECLSPEC Uint32 SDLCALL SDL_rand_bits(void);

/**
 * Generate a pseudo-random number less than n for positive n
 *
 * The method used is faster and of better quality than `rand() % n`. Odds are
 * roughly 99.9% even for n = 1 million. Evenness is better for smaller n, and
 * much worse as n gets bigger.
 *
 * Example: to simulate a d6 use `SDL_rand_r(state, 6) + 1` The +1 converts
 * 0..5 to 1..6
 *
 * If you want to generate a pseudo-random number in the full range of Sint32,
 * you should use: (Sint32)SDL_rand_bits_r(state)
 *
 * There are no guarantees as to the quality of the random sequence produced,
 * and this should not be used for security (cryptography, passwords) or where
 * money is on the line (loot-boxes, casinos). There are many random number
 * libraries available with different characteristics and you should pick one
 * of those to meet any serious needs.
 *
 * \param state a pointer to the current random number state, this may not be
 *              NULL.
 * \param n the number of possible outcomes. n must be positive.
 * \returns a random value in the range of [0 .. n-1].
 *
 * \threadsafety This function is thread-safe, as long as the state pointer
 *               isn't shared between threads.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_rand
 * \sa SDL_rand_bits_r
 * \sa SDL_randf_r
 */
extern SDL_DECLSPEC Sint32 SDLCALL SDL_rand_r(Uint64 *state, Sint32 n);

/**
 * Generate a uniform pseudo-random floating point number less than 1.0
 *
 * If you want reproducible output, be sure to initialize with SDL_srand()
 * first.
 *
 * There are no guarantees as to the quality of the random sequence produced,
 * and this should not be used for security (cryptography, passwords) or where
 * money is on the line (loot-boxes, casinos). There are many random number
 * libraries available with different characteristics and you should pick one
 * of those to meet any serious needs.
 *
 * \param state a pointer to the current random number state, this may not be
 *              NULL.
 * \returns a random value in the range of [0.0, 1.0).
 *
 * \threadsafety This function is thread-safe, as long as the state pointer
 *               isn't shared between threads.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_rand_bits_r
 * \sa SDL_rand_r
 * \sa SDL_randf
 */
extern SDL_DECLSPEC float SDLCALL SDL_randf_r(Uint64 *state);

/**
 * Generate 32 pseudo-random bits.
 *
 * You likely want to use SDL_rand_r() to get a psuedo-random number instead.
 *
 * There are no guarantees as to the quality of the random sequence produced,
 * and this should not be used for security (cryptography, passwords) or where
 * money is on the line (loot-boxes, casinos). There are many random number
 * libraries available with different characteristics and you should pick one
 * of those to meet any serious needs.
 *
 * \param state a pointer to the current random number state, this may not be
 *              NULL.
 * \returns a random value in the range of [0-SDL_MAX_UINT32].
 *
 * \threadsafety This function is thread-safe, as long as the state pointer
 *               isn't shared between threads.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_rand_r
 * \sa SDL_randf_r
 */
extern SDL_DECLSPEC Uint32 SDLCALL SDL_rand_bits_r(Uint64 *state);

#ifndef SDL_PI_D

/**
 * The value of Pi, as a double-precision floating point literal.
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_PI_F
 */
#define SDL_PI_D   3.141592653589793238462643383279502884       /**< pi (double) */
#endif

#ifndef SDL_PI_F

/**
 * The value of Pi, as a single-precision floating point literal.
 *
 * \since This macro is available since SDL 3.1.3.
 *
 * \sa SDL_PI_D
 */
#define SDL_PI_F   3.141592653589793238462643383279502884F      /**< pi (float) */
#endif

/**
 * Compute the arc cosine of `x`.
 *
 * The definition of `y = acos(x)` is `x = cos(y)`.
 *
 * Domain: `-1 <= x <= 1`
 *
 * Range: `0 <= y <= Pi`
 *
 * This function operates on double-precision floating point values, use
 * SDL_acosf for single-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value.
 * \returns arc cosine of `x`, in radians.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_acosf
 * \sa SDL_asin
 * \sa SDL_cos
 */
extern SDL_DECLSPEC double SDLCALL SDL_acos(double x);

/**
 * Compute the arc cosine of `x`.
 *
 * The definition of `y = acos(x)` is `x = cos(y)`.
 *
 * Domain: `-1 <= x <= 1`
 *
 * Range: `0 <= y <= Pi`
 *
 * This function operates on single-precision floating point values, use
 * SDL_acos for double-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value.
 * \returns arc cosine of `x`, in radians.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_acos
 * \sa SDL_asinf
 * \sa SDL_cosf
 */
extern SDL_DECLSPEC float SDLCALL SDL_acosf(float x);

/**
 * Compute the arc sine of `x`.
 *
 * The definition of `y = asin(x)` is `x = sin(y)`.
 *
 * Domain: `-1 <= x <= 1`
 *
 * Range: `-Pi/2 <= y <= Pi/2`
 *
 * This function operates on double-precision floating point values, use
 * SDL_asinf for single-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value.
 * \returns arc sine of `x`, in radians.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_asinf
 * \sa SDL_acos
 * \sa SDL_sin
 */
extern SDL_DECLSPEC double SDLCALL SDL_asin(double x);

/**
 * Compute the arc sine of `x`.
 *
 * The definition of `y = asin(x)` is `x = sin(y)`.
 *
 * Domain: `-1 <= x <= 1`
 *
 * Range: `-Pi/2 <= y <= Pi/2`
 *
 * This function operates on single-precision floating point values, use
 * SDL_asin for double-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value.
 * \returns arc sine of `x`, in radians.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_asin
 * \sa SDL_acosf
 * \sa SDL_sinf
 */
extern SDL_DECLSPEC float SDLCALL SDL_asinf(float x);

/**
 * Compute the arc tangent of `x`.
 *
 * The definition of `y = atan(x)` is `x = tan(y)`.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `-Pi/2 <= y <= Pi/2`
 *
 * This function operates on double-precision floating point values, use
 * SDL_atanf for single-precision floats.
 *
 * To calculate the arc tangent of y / x, use SDL_atan2.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value.
 * \returns arc tangent of of `x` in radians, or 0 if `x = 0`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_atanf
 * \sa SDL_atan2
 * \sa SDL_tan
 */
extern SDL_DECLSPEC double SDLCALL SDL_atan(double x);

/**
 * Compute the arc tangent of `x`.
 *
 * The definition of `y = atan(x)` is `x = tan(y)`.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `-Pi/2 <= y <= Pi/2`
 *
 * This function operates on single-precision floating point values, use
 * SDL_atan for dboule-precision floats.
 *
 * To calculate the arc tangent of y / x, use SDL_atan2f.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value.
 * \returns arc tangent of of `x` in radians, or 0 if `x = 0`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_atan
 * \sa SDL_atan2f
 * \sa SDL_tanf
 */
extern SDL_DECLSPEC float SDLCALL SDL_atanf(float x);

/**
 * Compute the arc tangent of `y / x`, using the signs of x and y to adjust
 * the result's quadrant.
 *
 * The definition of `z = atan2(x, y)` is `y = x tan(z)`, where the quadrant
 * of z is determined based on the signs of x and y.
 *
 * Domain: `-INF <= x <= INF`, `-INF <= y <= INF`
 *
 * Range: `-Pi/2 <= y <= Pi/2`
 *
 * This function operates on double-precision floating point values, use
 * SDL_atan2f for single-precision floats.
 *
 * To calculate the arc tangent of a single value, use SDL_atan.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param y floating point value of the numerator (y coordinate).
 * \param x floating point value of the denominator (x coordinate).
 * \returns arc tangent of of `y / x` in radians, or, if `x = 0`, either
 *          `-Pi/2`, `0`, or `Pi/2`, depending on the value of `y`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_atan2f
 * \sa SDL_atan
 * \sa SDL_tan
 */
extern SDL_DECLSPEC double SDLCALL SDL_atan2(double y, double x);

/**
 * Compute the arc tangent of `y / x`, using the signs of x and y to adjust
 * the result's quadrant.
 *
 * The definition of `z = atan2(x, y)` is `y = x tan(z)`, where the quadrant
 * of z is determined based on the signs of x and y.
 *
 * Domain: `-INF <= x <= INF`, `-INF <= y <= INF`
 *
 * Range: `-Pi/2 <= y <= Pi/2`
 *
 * This function operates on single-precision floating point values, use
 * SDL_atan2 for double-precision floats.
 *
 * To calculate the arc tangent of a single value, use SDL_atanf.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param y floating point value of the numerator (y coordinate).
 * \param x floating point value of the denominator (x coordinate).
 * \returns arc tangent of of `y / x` in radians, or, if `x = 0`, either
 *          `-Pi/2`, `0`, or `Pi/2`, depending on the value of `y`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_atan2f
 * \sa SDL_atan
 * \sa SDL_tan
 */
extern SDL_DECLSPEC float SDLCALL SDL_atan2f(float y, float x);

/**
 * Compute the ceiling of `x`.
 *
 * The ceiling of `x` is the smallest integer `y` such that `y > x`, i.e `x`
 * rounded up to the nearest integer.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `-INF <= y <= INF`, y integer
 *
 * This function operates on double-precision floating point values, use
 * SDL_ceilf for single-precision floats.
 *
 * \param x floating point value.
 * \returns the ceiling of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_ceilf
 * \sa SDL_floor
 * \sa SDL_trunc
 * \sa SDL_round
 * \sa SDL_lround
 */
extern SDL_DECLSPEC double SDLCALL SDL_ceil(double x);

/**
 * Compute the ceiling of `x`.
 *
 * The ceiling of `x` is the smallest integer `y` such that `y > x`, i.e `x`
 * rounded up to the nearest integer.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `-INF <= y <= INF`, y integer
 *
 * This function operates on single-precision floating point values, use
 * SDL_ceil for double-precision floats.
 *
 * \param x floating point value.
 * \returns the ceiling of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_ceil
 * \sa SDL_floorf
 * \sa SDL_truncf
 * \sa SDL_roundf
 * \sa SDL_lroundf
 */
extern SDL_DECLSPEC float SDLCALL SDL_ceilf(float x);

/**
 * Copy the sign of one floating-point value to another.
 *
 * The definition of copysign is that ``copysign(x, y) = abs(x) * sign(y)``.
 *
 * Domain: `-INF <= x <= INF`, ``-INF <= y <= f``
 *
 * Range: `-INF <= z <= INF`
 *
 * This function operates on double-precision floating point values, use
 * SDL_copysignf for single-precision floats.
 *
 * \param x floating point value to use as the magnitude.
 * \param y floating point value to use as the sign.
 * \returns the floating point value with the sign of y and the magnitude of
 *          x.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_copysignf
 * \sa SDL_fabs
 */
extern SDL_DECLSPEC double SDLCALL SDL_copysign(double x, double y);

/**
 * Copy the sign of one floating-point value to another.
 *
 * The definition of copysign is that ``copysign(x, y) = abs(x) * sign(y)``.
 *
 * Domain: `-INF <= x <= INF`, ``-INF <= y <= f``
 *
 * Range: `-INF <= z <= INF`
 *
 * This function operates on single-precision floating point values, use
 * SDL_copysign for double-precision floats.
 *
 * \param x floating point value to use as the magnitude.
 * \param y floating point value to use as the sign.
 * \returns the floating point value with the sign of y and the magnitude of
 *          x.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_copysignf
 * \sa SDL_fabsf
 */
extern SDL_DECLSPEC float SDLCALL SDL_copysignf(float x, float y);

/**
 * Compute the cosine of `x`.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `-1 <= y <= 1`
 *
 * This function operates on double-precision floating point values, use
 * SDL_cosf for single-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value, in radians.
 * \returns cosine of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_cosf
 * \sa SDL_acos
 * \sa SDL_sin
 */
extern SDL_DECLSPEC double SDLCALL SDL_cos(double x);

/**
 * Compute the cosine of `x`.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `-1 <= y <= 1`
 *
 * This function operates on single-precision floating point values, use
 * SDL_cos for double-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value, in radians.
 * \returns cosine of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_cos
 * \sa SDL_acosf
 * \sa SDL_sinf
 */
extern SDL_DECLSPEC float SDLCALL SDL_cosf(float x);

/**
 * Compute the exponential of `x`.
 *
 * The definition of `y = exp(x)` is `y = e^x`, where `e` is the base of the
 * natural logarithm. The inverse is the natural logarithm, SDL_log.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `0 <= y <= INF`
 *
 * The output will overflow if `exp(x)` is too large to be represented.
 *
 * This function operates on double-precision floating point values, use
 * SDL_expf for single-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value.
 * \returns value of `e^x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_expf
 * \sa SDL_log
 */
extern SDL_DECLSPEC double SDLCALL SDL_exp(double x);

/**
 * Compute the exponential of `x`.
 *
 * The definition of `y = exp(x)` is `y = e^x`, where `e` is the base of the
 * natural logarithm. The inverse is the natural logarithm, SDL_logf.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `0 <= y <= INF`
 *
 * The output will overflow if `exp(x)` is too large to be represented.
 *
 * This function operates on single-precision floating point values, use
 * SDL_exp for double-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value.
 * \returns value of `e^x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_exp
 * \sa SDL_logf
 */
extern SDL_DECLSPEC float SDLCALL SDL_expf(float x);

/**
 * Compute the absolute value of `x`
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `0 <= y <= INF`
 *
 * This function operates on double-precision floating point values, use
 * SDL_copysignf for single-precision floats.
 *
 * \param x floating point value to use as the magnitude.
 * \returns the absolute value of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_fabsf
 */
extern SDL_DECLSPEC double SDLCALL SDL_fabs(double x);

/**
 * Compute the absolute value of `x`
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `0 <= y <= INF`
 *
 * This function operates on single-precision floating point values, use
 * SDL_copysignf for double-precision floats.
 *
 * \param x floating point value to use as the magnitude.
 * \returns the absolute value of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_fabs
 */
extern SDL_DECLSPEC float SDLCALL SDL_fabsf(float x);

/**
 * Compute the floor of `x`.
 *
 * The floor of `x` is the largest integer `y` such that `y > x`, i.e `x`
 * rounded down to the nearest integer.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `-INF <= y <= INF`, y integer
 *
 * This function operates on double-precision floating point values, use
 * SDL_floorf for single-precision floats.
 *
 * \param x floating point value.
 * \returns the floor of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_floorf
 * \sa SDL_ceil
 * \sa SDL_trunc
 * \sa SDL_round
 * \sa SDL_lround
 */
extern SDL_DECLSPEC double SDLCALL SDL_floor(double x);

/**
 * Compute the floor of `x`.
 *
 * The floor of `x` is the largest integer `y` such that `y > x`, i.e `x`
 * rounded down to the nearest integer.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `-INF <= y <= INF`, y integer
 *
 * This function operates on single-precision floating point values, use
 * SDL_floorf for double-precision floats.
 *
 * \param x floating point value.
 * \returns the floor of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_floor
 * \sa SDL_ceilf
 * \sa SDL_truncf
 * \sa SDL_roundf
 * \sa SDL_lroundf
 */
extern SDL_DECLSPEC float SDLCALL SDL_floorf(float x);

/**
 * Truncate `x` to an integer.
 *
 * Rounds `x` to the next closest integer to 0. This is equivalent to removing
 * the fractional part of `x`, leaving only the integer part.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `-INF <= y <= INF`, y integer
 *
 * This function operates on double-precision floating point values, use
 * SDL_truncf for single-precision floats.
 *
 * \param x floating point value.
 * \returns `x` truncated to an integer.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_truncf
 * \sa SDL_fmod
 * \sa SDL_ceil
 * \sa SDL_floor
 * \sa SDL_round
 * \sa SDL_lround
 */
extern SDL_DECLSPEC double SDLCALL SDL_trunc(double x);

/**
 * Truncate `x` to an integer.
 *
 * Rounds `x` to the next closest integer to 0. This is equivalent to removing
 * the fractional part of `x`, leaving only the integer part.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `-INF <= y <= INF`, y integer
 *
 * This function operates on single-precision floating point values, use
 * SDL_truncf for double-precision floats.
 *
 * \param x floating point value.
 * \returns `x` truncated to an integer.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_trunc
 * \sa SDL_fmodf
 * \sa SDL_ceilf
 * \sa SDL_floorf
 * \sa SDL_roundf
 * \sa SDL_lroundf
 */
extern SDL_DECLSPEC float SDLCALL SDL_truncf(float x);

/**
 * Return the floating-point remainder of `x / y`
 *
 * Divides `x` by `y`, and returns the remainder.
 *
 * Domain: `-INF <= x <= INF`, `-INF <= y <= INF`, `y != 0`
 *
 * Range: `-y <= z <= y`
 *
 * This function operates on double-precision floating point values, use
 * SDL_fmodf for single-precision floats.
 *
 * \param x the numerator.
 * \param y the denominator. Must not be 0.
 * \returns the remainder of `x / y`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_fmodf
 * \sa SDL_modf
 * \sa SDL_trunc
 * \sa SDL_ceil
 * \sa SDL_floor
 * \sa SDL_round
 * \sa SDL_lround
 */
extern SDL_DECLSPEC double SDLCALL SDL_fmod(double x, double y);

/**
 * Return the floating-point remainder of `x / y`
 *
 * Divides `x` by `y`, and returns the remainder.
 *
 * Domain: `-INF <= x <= INF`, `-INF <= y <= INF`, `y != 0`
 *
 * Range: `-y <= z <= y`
 *
 * This function operates on single-precision floating point values, use
 * SDL_fmod for single-precision floats.
 *
 * \param x the numerator.
 * \param y the denominator. Must not be 0.
 * \returns the remainder of `x / y`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_fmod
 * \sa SDL_truncf
 * \sa SDL_modff
 * \sa SDL_ceilf
 * \sa SDL_floorf
 * \sa SDL_roundf
 * \sa SDL_lroundf
 */
extern SDL_DECLSPEC float SDLCALL SDL_fmodf(float x, float y);

/**
 * Return whether the value is infinity.
 *
 * \param x double-precision floating point value.
 * \returns non-zero if the value is infinity, 0 otherwise.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_isinff
 */
extern SDL_DECLSPEC int SDLCALL SDL_isinf(double x);

/**
 * Return whether the value is infinity.
 *
 * \param x floating point value.
 * \returns non-zero if the value is infinity, 0 otherwise.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_isinf
 */
extern SDL_DECLSPEC int SDLCALL SDL_isinff(float x);

/**
 * Return whether the value is NaN.
 *
 * \param x double-precision floating point value.
 * \returns non-zero if the value is NaN, 0 otherwise.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_isnanf
 */
extern SDL_DECLSPEC int SDLCALL SDL_isnan(double x);

/**
 * Return whether the value is NaN.
 *
 * \param x floating point value.
 * \returns non-zero if the value is NaN, 0 otherwise.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_isnan
 */
extern SDL_DECLSPEC int SDLCALL SDL_isnanf(float x);

/**
 * Compute the natural logarithm of `x`.
 *
 * Domain: `0 < x <= INF`
 *
 * Range: `-INF <= y <= INF`
 *
 * It is an error for `x` to be less than or equal to 0.
 *
 * This function operates on double-precision floating point values, use
 * SDL_logf for single-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value. Must be greater than 0.
 * \returns the natural logarithm of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_logf
 * \sa SDL_log10
 * \sa SDL_exp
 */
extern SDL_DECLSPEC double SDLCALL SDL_log(double x);

/**
 * Compute the natural logarithm of `x`.
 *
 * Domain: `0 < x <= INF`
 *
 * Range: `-INF <= y <= INF`
 *
 * It is an error for `x` to be less than or equal to 0.
 *
 * This function operates on single-precision floating point values, use
 * SDL_log for double-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value. Must be greater than 0.
 * \returns the natural logarithm of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_log
 * \sa SDL_expf
 */
extern SDL_DECLSPEC float SDLCALL SDL_logf(float x);

/**
 * Compute the base-10 logarithm of `x`.
 *
 * Domain: `0 < x <= INF`
 *
 * Range: `-INF <= y <= INF`
 *
 * It is an error for `x` to be less than or equal to 0.
 *
 * This function operates on double-precision floating point values, use
 * SDL_log10f for single-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value. Must be greater than 0.
 * \returns the logarithm of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_log10f
 * \sa SDL_log
 * \sa SDL_pow
 */
extern SDL_DECLSPEC double SDLCALL SDL_log10(double x);

/**
 * Compute the base-10 logarithm of `x`.
 *
 * Domain: `0 < x <= INF`
 *
 * Range: `-INF <= y <= INF`
 *
 * It is an error for `x` to be less than or equal to 0.
 *
 * This function operates on single-precision floating point values, use
 * SDL_log10 for double-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value. Must be greater than 0.
 * \returns the logarithm of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_log10
 * \sa SDL_logf
 * \sa SDL_powf
 */
extern SDL_DECLSPEC float SDLCALL SDL_log10f(float x);

/**
 * Split `x` into integer and fractional parts
 *
 * This function operates on double-precision floating point values, use
 * SDL_modff for single-precision floats.
 *
 * \param x floating point value.
 * \param y output pointer to store the integer part of `x`.
 * \returns the fractional part of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_modff
 * \sa SDL_trunc
 * \sa SDL_fmod
 */
extern SDL_DECLSPEC double SDLCALL SDL_modf(double x, double *y);

/**
 * Split `x` into integer and fractional parts
 *
 * This function operates on single-precision floating point values, use
 * SDL_modf for double-precision floats.
 *
 * \param x floating point value.
 * \param y output pointer to store the integer part of `x`.
 * \returns the fractional part of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_modf
 * \sa SDL_truncf
 * \sa SDL_fmodf
 */
extern SDL_DECLSPEC float SDLCALL SDL_modff(float x, float *y);

/**
 * Raise `x` to the power `y`
 *
 * Domain: `-INF <= x <= INF`, `-INF <= y <= INF`
 *
 * Range: `-INF <= z <= INF`
 *
 * If `y` is the base of the natural logarithm (e), consider using SDL_exp
 * instead.
 *
 * This function operates on double-precision floating point values, use
 * SDL_powf for single-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x the base.
 * \param y the exponent.
 * \returns `x` raised to the power `y`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_powf
 * \sa SDL_exp
 * \sa SDL_log
 */
extern SDL_DECLSPEC double SDLCALL SDL_pow(double x, double y);

/**
 * Raise `x` to the power `y`
 *
 * Domain: `-INF <= x <= INF`, `-INF <= y <= INF`
 *
 * Range: `-INF <= z <= INF`
 *
 * If `y` is the base of the natural logarithm (e), consider using SDL_exp
 * instead.
 *
 * This function operates on single-precision floating point values, use
 * SDL_powf for double-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x the base.
 * \param y the exponent.
 * \returns `x` raised to the power `y`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_pow
 * \sa SDL_expf
 * \sa SDL_logf
 */
extern SDL_DECLSPEC float SDLCALL SDL_powf(float x, float y);

/**
 * Round `x` to the nearest integer.
 *
 * Rounds `x` to the nearest integer. Values halfway between integers will be
 * rounded away from zero.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `-INF <= y <= INF`, y integer
 *
 * This function operates on double-precision floating point values, use
 * SDL_roundf for single-precision floats. To get the result as an integer
 * type, use SDL_lround.
 *
 * \param x floating point value.
 * \returns the nearest integer to `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_roundf
 * \sa SDL_lround
 * \sa SDL_floor
 * \sa SDL_ceil
 * \sa SDL_trunc
 */
extern SDL_DECLSPEC double SDLCALL SDL_round(double x);

/**
 * Round `x` to the nearest integer.
 *
 * Rounds `x` to the nearest integer. Values halfway between integers will be
 * rounded away from zero.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `-INF <= y <= INF`, y integer
 *
 * This function operates on double-precision floating point values, use
 * SDL_roundf for single-precision floats. To get the result as an integer
 * type, use SDL_lroundf.
 *
 * \param x floating point value.
 * \returns the nearest integer to `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_round
 * \sa SDL_lroundf
 * \sa SDL_floorf
 * \sa SDL_ceilf
 * \sa SDL_truncf
 */
extern SDL_DECLSPEC float SDLCALL SDL_roundf(float x);

/**
 * Round `x` to the nearest integer representable as a long
 *
 * Rounds `x` to the nearest integer. Values halfway between integers will be
 * rounded away from zero.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `MIN_LONG <= y <= MAX_LONG`
 *
 * This function operates on double-precision floating point values, use
 * SDL_lround for single-precision floats. To get the result as a
 * floating-point type, use SDL_round.
 *
 * \param x floating point value.
 * \returns the nearest integer to `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_lroundf
 * \sa SDL_round
 * \sa SDL_floor
 * \sa SDL_ceil
 * \sa SDL_trunc
 */
extern SDL_DECLSPEC long SDLCALL SDL_lround(double x);

/**
 * Round `x` to the nearest integer representable as a long
 *
 * Rounds `x` to the nearest integer. Values halfway between integers will be
 * rounded away from zero.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `MIN_LONG <= y <= MAX_LONG`
 *
 * This function operates on single-precision floating point values, use
 * SDL_lroundf for double-precision floats. To get the result as a
 * floating-point type, use SDL_roundf,
 *
 * \param x floating point value.
 * \returns the nearest integer to `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_lround
 * \sa SDL_roundf
 * \sa SDL_floorf
 * \sa SDL_ceilf
 * \sa SDL_truncf
 */
extern SDL_DECLSPEC long SDLCALL SDL_lroundf(float x);

/**
 * Scale `x` by an integer power of two.
 *
 * Multiplies `x` by the `n`th power of the floating point radix (always 2).
 *
 * Domain: `-INF <= x <= INF`, `n` integer
 *
 * Range: `-INF <= y <= INF`
 *
 * This function operates on double-precision floating point values, use
 * SDL_scalbnf for single-precision floats.
 *
 * \param x floating point value to be scaled.
 * \param n integer exponent.
 * \returns `x * 2^n`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_scalbnf
 * \sa SDL_pow
 */
extern SDL_DECLSPEC double SDLCALL SDL_scalbn(double x, int n);

/**
 * Scale `x` by an integer power of two.
 *
 * Multiplies `x` by the `n`th power of the floating point radix (always 2).
 *
 * Domain: `-INF <= x <= INF`, `n` integer
 *
 * Range: `-INF <= y <= INF`
 *
 * This function operates on single-precision floating point values, use
 * SDL_scalbn for double-precision floats.
 *
 * \param x floating point value to be scaled.
 * \param n integer exponent.
 * \returns `x * 2^n`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_scalbn
 * \sa SDL_powf
 */
extern SDL_DECLSPEC float SDLCALL SDL_scalbnf(float x, int n);

/**
 * Compute the sine of `x`.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `-1 <= y <= 1`
 *
 * This function operates on double-precision floating point values, use
 * SDL_sinf for single-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value, in radians.
 * \returns sine of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_sinf
 * \sa SDL_asin
 * \sa SDL_cos
 */
extern SDL_DECLSPEC double SDLCALL SDL_sin(double x);

/**
 * Compute the sine of `x`.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `-1 <= y <= 1`
 *
 * This function operates on single-precision floating point values, use
 * SDL_sinf for double-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value, in radians.
 * \returns sine of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_sin
 * \sa SDL_asinf
 * \sa SDL_cosf
 */
extern SDL_DECLSPEC float SDLCALL SDL_sinf(float x);

/**
 * Compute the square root of `x`.
 *
 * Domain: `0 <= x <= INF`
 *
 * Range: `0 <= y <= INF`
 *
 * This function operates on double-precision floating point values, use
 * SDL_sqrtf for single-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value. Must be greater than or equal to 0.
 * \returns square root of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_sqrtf
 */
extern SDL_DECLSPEC double SDLCALL SDL_sqrt(double x);

/**
 * Compute the square root of `x`.
 *
 * Domain: `0 <= x <= INF`
 *
 * Range: `0 <= y <= INF`
 *
 * This function operates on single-precision floating point values, use
 * SDL_sqrt for double-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value. Must be greater than or equal to 0.
 * \returns square root of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_sqrt
 */
extern SDL_DECLSPEC float SDLCALL SDL_sqrtf(float x);

/**
 * Compute the tangent of `x`.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `-INF <= y <= INF`
 *
 * This function operates on double-precision floating point values, use
 * SDL_tanf for single-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value, in radians.
 * \returns tangent of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_tanf
 * \sa SDL_sin
 * \sa SDL_cos
 * \sa SDL_atan
 * \sa SDL_atan2
 */
extern SDL_DECLSPEC double SDLCALL SDL_tan(double x);

/**
 * Compute the tangent of `x`.
 *
 * Domain: `-INF <= x <= INF`
 *
 * Range: `-INF <= y <= INF`
 *
 * This function operates on single-precision floating point values, use
 * SDL_tanf for double-precision floats.
 *
 * This function may use a different approximation across different versions,
 * platforms and configurations. i.e, it can return a different value given
 * the same input on different machines or operating systems, or if SDL is
 * updated.
 *
 * \param x floating point value, in radians.
 * \returns tangent of `x`.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_tan
 * \sa SDL_sinf
 * \sa SDL_cosf
 * \sa SDL_atanf
 * \sa SDL_atan2f
 */
extern SDL_DECLSPEC float SDLCALL SDL_tanf(float x);

/**
 * An opaque handle representing string encoding conversion state.
 *
 * \since This datatype is available since SDL 3.1.3.
 *
 * \sa SDL_iconv_open
 */
typedef struct SDL_iconv_data_t *SDL_iconv_t;

/**
 * This function allocates a context for the specified character set
 * conversion.
 *
 * \param tocode The target character encoding, must not be NULL.
 * \param fromcode The source character encoding, must not be NULL.
 * \returns a handle that must be freed with SDL_iconv_close, or
 *          SDL_ICONV_ERROR on failure.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_iconv
 * \sa SDL_iconv_close
 * \sa SDL_iconv_string
 */
extern SDL_DECLSPEC SDL_iconv_t SDLCALL SDL_iconv_open(const char *tocode,
                                                   const char *fromcode);

/**
 * This function frees a context used for character set conversion.
 *
 * \param cd The character set conversion handle.
 * \returns 0 on success, or -1 on failure.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_iconv
 * \sa SDL_iconv_open
 * \sa SDL_iconv_string
 */
extern SDL_DECLSPEC int SDLCALL SDL_iconv_close(SDL_iconv_t cd);

/**
 * This function converts text between encodings, reading from and writing to
 * a buffer.
 *
 * It returns the number of succesful conversions on success. On error,
 * SDL_ICONV_E2BIG is returned when the output buffer is too small, or
 * SDL_ICONV_EILSEQ is returned when an invalid input sequence is encountered,
 * or SDL_ICONV_EINVAL is returned when an incomplete input sequence is
 * encountered.
 *
 * On exit:
 *
 * - inbuf will point to the beginning of the next multibyte sequence. On
 *   error, this is the location of the problematic input sequence. On
 *   success, this is the end of the input sequence.
 * - inbytesleft will be set to the number of bytes left to convert, which
 *   will be 0 on success.
 * - outbuf will point to the location where to store the next output byte.
 * - outbytesleft will be set to the number of bytes left in the output
 *   buffer.
 *
 * \param cd The character set conversion context, created in
 *           SDL_iconv_open().
 * \param inbuf Address of variable that points to the first character of the
 *              input sequence.
 * \param inbytesleft The number of bytes in the input buffer.
 * \param outbuf Address of variable that points to the output buffer.
 * \param outbytesleft The number of bytes in the output buffer.
 * \returns the number of conversions on success, or a negative error code.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_iconv_open
 * \sa SDL_iconv_close
 * \sa SDL_iconv_string
 */
extern SDL_DECLSPEC size_t SDLCALL SDL_iconv(SDL_iconv_t cd, const char **inbuf,
                                         size_t *inbytesleft, char **outbuf,
                                         size_t *outbytesleft);

#define SDL_ICONV_ERROR     (size_t)-1  /**< Generic error. Check SDL_GetError()? */
#define SDL_ICONV_E2BIG     (size_t)-2  /**< Output buffer was too small. */
#define SDL_ICONV_EILSEQ    (size_t)-3  /**< Invalid input sequence was encountered. */
#define SDL_ICONV_EINVAL    (size_t)-4  /**< Incomplete input sequence was encountered. */


/**
 * Helper function to convert a string's encoding in one call.
 *
 * This function converts a buffer or string between encodings in one pass.
 *
 * The string does not need to be NULL-terminated; this function operates on
 * the number of bytes specified in `inbytesleft` whether there is a NULL
 * character anywhere in the buffer.
 *
 * The returned string is owned by the caller, and should be passed to
 * SDL_free when no longer needed.
 *
 * \param tocode the character encoding of the output string. Examples are
 *               "UTF-8", "UCS-4", etc.
 * \param fromcode the character encoding of data in `inbuf`.
 * \param inbuf the string to convert to a different encoding.
 * \param inbytesleft the size of the input string _in bytes_.
 * \returns a new string, converted to the new encoding, or NULL on error.
 *
 * \since This function is available since SDL 3.1.3.
 *
 * \sa SDL_iconv_open
 * \sa SDL_iconv_close
 * \sa SDL_iconv
 */
extern SDL_DECLSPEC char * SDLCALL SDL_iconv_string(const char *tocode,
                                               const char *fromcode,
                                               const char *inbuf,
                                               size_t inbytesleft);

/* Some helper macros for common SDL_iconv_string cases... */

/**
 * Convert a UTF-8 string to the current locale's character encoding.
 *
 * This is a helper macro that might be more clear than calling
 * SDL_iconv_string directly. However, it double-evaluates its parameter, so
 * do not use an expression with side-effects here.
 *
 * \param S the string to convert.
 * \returns a new string, converted to the new encoding, or NULL on error.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_iconv_utf8_locale(S)    SDL_iconv_string("", "UTF-8", S, SDL_strlen(S)+1)

/**
 * Convert a UTF-8 string to UCS-2.
 *
 * This is a helper macro that might be more clear than calling
 * SDL_iconv_string directly. However, it double-evaluates its parameter, so
 * do not use an expression with side-effects here.
 *
 * \param S the string to convert.
 * \returns a new string, converted to the new encoding, or NULL on error.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_iconv_utf8_ucs2(S)      (Uint16 *)SDL_iconv_string("UCS-2", "UTF-8", S, SDL_strlen(S)+1)

/**
 * Convert a UTF-8 string to UCS-4.
 *
 * This is a helper macro that might be more clear than calling
 * SDL_iconv_string directly. However, it double-evaluates its parameter, so
 * do not use an expression with side-effects here.
 *
 * \param S the string to convert.
 * \returns a new string, converted to the new encoding, or NULL on error.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_iconv_utf8_ucs4(S)      (Uint32 *)SDL_iconv_string("UCS-4", "UTF-8", S, SDL_strlen(S)+1)

/**
 * Convert a wchar_t string to UTF-8.
 *
 * This is a helper macro that might be more clear than calling
 * SDL_iconv_string directly. However, it double-evaluates its parameter, so
 * do not use an expression with side-effects here.
 *
 * \param S the string to convert.
 * \returns a new string, converted to the new encoding, or NULL on error.
 *
 * \since This macro is available since SDL 3.1.3.
 */
#define SDL_iconv_wchar_utf8(S)     SDL_iconv_string("UTF-8", "WCHAR_T", (char *)S, (SDL_wcslen(S)+1)*sizeof(wchar_t))


/* force builds using Clang's static analysis tools to use literal C runtime
   here, since there are possibly tests that are ineffective otherwise. */
#if defined(__clang_analyzer__) && !defined(SDL_DISABLE_ANALYZE_MACROS)

/* The analyzer knows about strlcpy even when the system doesn't provide it */
#if !defined(HAVE_STRLCPY) && !defined(strlcpy)
size_t strlcpy(char *dst, const char *src, size_t size);
#endif

/* The analyzer knows about strlcat even when the system doesn't provide it */
#if !defined(HAVE_STRLCAT) && !defined(strlcat)
size_t strlcat(char *dst, const char *src, size_t size);
#endif

#if !defined(HAVE_WCSLCPY) && !defined(wcslcpy)
size_t wcslcpy(wchar_t *dst, const wchar_t *src, size_t size);
#endif

#if !defined(HAVE_WCSLCAT) && !defined(wcslcat)
size_t wcslcat(wchar_t *dst, const wchar_t *src, size_t size);
#endif

/* strdup is not ANSI but POSIX, and its prototype might be hidden... */
char *strdup(const char *str);

/* Starting LLVM 16, the analyser errors out if these functions do not have
   their prototype defined (clang-diagnostic-implicit-function-declaration) */
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>

#define SDL_malloc malloc
#define SDL_calloc calloc
#define SDL_realloc realloc
#define SDL_free free
#ifndef SDL_memcpy
#define SDL_memcpy memcpy
#endif
#ifndef SDL_memmove
#define SDL_memmove memmove
#endif
#ifndef SDL_memset
#define SDL_memset memset
#endif
#define SDL_memcmp memcmp
#define SDL_strlcpy strlcpy
#define SDL_strlcat strlcat
#define SDL_strlen strlen
#define SDL_wcslen wcslen
#define SDL_wcslcpy wcslcpy
#define SDL_wcslcat wcslcat
#define SDL_strdup strdup
#define SDL_wcsdup wcsdup
#define SDL_strchr strchr
#define SDL_strrchr strrchr
#define SDL_strstr strstr
#define SDL_wcsstr wcsstr
#define SDL_strtok_r strtok_r
#define SDL_strcmp strcmp
#define SDL_wcscmp wcscmp
#define SDL_strncmp strncmp
#define SDL_wcsncmp wcsncmp
#define SDL_strcasecmp strcasecmp
#define SDL_strncasecmp strncasecmp
#define SDL_strpbrk strpbrk
#define SDL_sscanf sscanf
#define SDL_vsscanf vsscanf
#define SDL_snprintf snprintf
#define SDL_vsnprintf vsnprintf
#endif

/**
 * Multiply two integers, checking for overflow.
 *
 * If `a * b` would overflow, return false.
 *
 * Otherwise store `a * b` via ret and return true.
 *
 * \param a the multiplicand.
 * \param b the multiplier.
 * \param ret on non-overflow output, stores the multiplication result, may
 *            not be NULL.
 * \returns false on overflow, true if result is multiplied without overflow.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
SDL_FORCE_INLINE bool SDL_size_mul_check_overflow(size_t a, size_t b, size_t *ret)
{
    if (a != 0 && b > SDL_SIZE_MAX / a) {
        return false;
    }
    *ret = a * b;
    return true;
}

#ifndef SDL_WIKI_DOCUMENTATION_SECTION
#if SDL_HAS_BUILTIN(__builtin_mul_overflow)
/* This needs to be wrapped in an inline rather than being a direct #define,
 * because __builtin_mul_overflow() is type-generic, but we want to be
 * consistent about interpreting a and b as size_t. */
SDL_FORCE_INLINE bool SDL_size_mul_check_overflow_builtin(size_t a, size_t b, size_t *ret)
{
    return (__builtin_mul_overflow(a, b, ret) == 0);
}
#define SDL_size_mul_check_overflow(a, b, ret) SDL_size_mul_check_overflow_builtin(a, b, ret)
#endif
#endif

/**
 * Add two integers, checking for overflow.
 *
 * If `a + b` would overflow, return false.
 *
 * Otherwise store `a + b` via ret and return true.
 *
 * \param a the first addend.
 * \param b the second addend.
 * \param ret on non-overflow output, stores the addition result, may not be
 *            NULL.
 * \returns false on overflow, true if result is added without overflow.
 *
 * \threadsafety It is safe to call this function from any thread.
 *
 * \since This function is available since SDL 3.1.3.
 */
SDL_FORCE_INLINE bool SDL_size_add_check_overflow(size_t a, size_t b, size_t *ret)
{
    if (b > SDL_SIZE_MAX - a) {
        return false;
    }
    *ret = a + b;
    return true;
}

#ifndef SDL_WIKI_DOCUMENTATION_SECTION
#if SDL_HAS_BUILTIN(__builtin_add_overflow)
/* This needs to be wrapped in an inline rather than being a direct #define,
 * the same as the call to __builtin_mul_overflow() above. */
SDL_FORCE_INLINE bool SDL_size_add_check_overflow_builtin(size_t a, size_t b, size_t *ret)
{
    return (__builtin_add_overflow(a, b, ret) == 0);
}
#define SDL_size_add_check_overflow(a, b, ret) SDL_size_add_check_overflow_builtin(a, b, ret)
#endif
#endif

/* This is a generic function pointer which should be cast to the type you expect */
#ifdef SDL_WIKI_DOCUMENTATION_SECTION

/**
 * A generic function pointer.
 *
 * In theory, generic function pointers should use this, instead of `void *`,
 * since some platforms could treat code addresses differently than data
 * addresses. Although in current times no popular platforms make this
 * distinction, it is more correct and portable to use the correct type for a
 * generic pointer.
 *
 * If for some reason you need to force this typedef to be an actual `void *`,
 * perhaps to work around a compiler or existing code, you can define
 * `SDL_FUNCTION_POINTER_IS_VOID_POINTER` before including any SDL headers.
 *
 * \since This datatype is available since SDL 3.1.3.
 */
typedef void (*SDL_FunctionPointer)(void);
#elif defined(SDL_FUNCTION_POINTER_IS_VOID_POINTER)
typedef void *SDL_FunctionPointer;
#else
typedef void (*SDL_FunctionPointer)(void);
#endif

/* Ends C function definitions when using C++ */
#ifdef __cplusplus
}
#endif
#include <SDL3/SDL_close_code.h>

#endif /* SDL_stdinc_h_ */