pocketpy/docs/quick-start/installation.md

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icon: dot label: 'Installation'

order: 100

Download the pocketpy.h on our GitHub Release page. And #include it in your project.

Compile flags

To compile it with your project, these flags must be set:

• --std=c++17 flag must be set
• Exception must be enabled
• RTTI is not required

!!! For maximum performance, we recommend to use clang++ with -O2 flag. !!!

Example

#include "pocketpy.h"

using namespace pkpy;

int main(){
    // Create a virtual machine
    VM* vm = new VM();
    
    // Hello world!
    vm->exec("print('Hello world!')", "main.py", EXEC_MODE);

    // Create a list
    vm->exec("a = [1, 2, 3]", "main.py", EXEC_MODE);

    // Eval the sum of the list
    PyObject* result = vm->exec("sum(a)", "<eval>", EVAL_MODE);
    std::cout << CAST(int, result);   // 6
    return 0;
}

Overview

pkpy's C++ interfaces are organized in an object-oriented way. All classes are located in pkpy namespace.

The most important class is the VM class. A VM instance is a python virtual machine which holds all necessary runtime states, including callstacks, modules, variables, etc.

You need to use the C++ new operator to create a VM instance.

VM* vm = new VM();

The constructor can take 2 extra parameters.

VM(bool use_stdio=true, bool enable_os=true)

• use_stdio, if true, the print() function outputs string to stdout. Error messages will be send to stderr; If false, they will be sent to an internal buffer. In the latter case, you need to read them via read_output manually.
• enable_os, whether to enable OS-related features or not. This setting controls the availability of some priviledged modules such os io and os as well as builtin function open.

When you are done with the VM instance, you need to use the C++ delete operator to free the memory.

delete vm;