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@@ -17,6 +17,48 @@ typedef bool (*py_CFunction)(int argc, py_Ref argv);
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If successful, the function should return `true` and set the return value in `py_retval()`. In case there is no return value, you should use `py_newnone(py_retval())`.
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If an error occurs, the function should raise an exception and return `false`.
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+## Steps
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+
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+Say you have a function `add` that takes two integers and returns their sum.
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+```c
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+int add(int a, int b) {
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+ return a + b;
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+}
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+```
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+
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+Here is how you can write the binding for it:
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+```c
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+// 1. Define a wrapper function with the signature `py_CFunction`.
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+bool py_add(int argc, py_Ref argv) {
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+ // 2. Check the number of arguments.
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+ PY_CHECK_ARGC(2);
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+ // 3. Check the type of arguments.
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+ PY_CHECK_ARG_TYPE(0, tp_int);
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+ PY_CHECK_ARG_TYPE(1, tp_int);
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+ // 4. Convert the arguments into C types.
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+ int _0 = py_toint(py_arg(0));
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+ int _1 = py_toint(py_arg(1));
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+ // 5. Call the original function.
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+ int res = add(_0, _1);
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+ // 6. Set the return value.
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+ py_newint(py_retval(), res);
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+ // 7. Return `true`.
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+ return true;
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+}
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+```
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+
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+Once you have the wrapper function, you can bind it to a python module via `py_bindfunc`.
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+```c
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+py_GlobalRef mod = py_getmodule("__main__");
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+py_bindfunc(mod, "add", py_add);
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+```
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+
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+Alternatively, you can use `py_bind` with a signature, which allows you to specify some default values.
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+```c
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+py_GlobalRef mod = py_getmodule("__main__");
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+py_bind(mod, "add(a, b=1)", py_add);
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+```
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+
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See also:
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+ [`py_bind`](/c-api/functions/#py_bind)
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+ [`py_bindmethod`](/c-api/functions/#py_bindmethod)
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