_multiarray_umath.cp39-win_amd64.pyd Crash

[a2448825647]

Embedding Python in C++. Crash process : Py_Initialize->"import numpy"->Py_Finalize->Py_Initialize->"import numpy".

Reproducing code example:

#include <Python.h>
#include <iostream>
#include <string>

int main()
{
    std::string command;
    while (true)
    {
        std::cin >> command;
        if (command == "1") {
            if (!Py_IsInitialized()) {
                Py_Initialize();
                std::cout << "Py_Initialize" << std::endl;
                PyRun_SimpleString("import sys");
                PyRun_SimpleString("sys.path.append('./')");
                PyRun_SimpleString("sys.path.append('D:/Document/VSProj/PythonVM/Scripts/')");
                PyRun_SimpleString("sys.path.append('D:/Document/VSProj/PythonVM/Scripts/yolov3')");
                PyRun_SimpleString("sys.path.append('D:/Document/VSProj/PythonVM/ThirdParty/PythonPackages')");
            }
        }
        if (command == "2") {
            if (Py_IsInitialized()) {
                Py_Finalize();
                std::cout << "Py_Finalize" << std::endl;
            }
        }
        if (command == "3") {
            std::cout << "run import numpy" << std::endl;
            PyRun_SimpleString("import numpy");
        }
        std::cout << "Input command" << std::endl;
    }
    return 0;
}

input : 1 3 2 1 3

Error message:

at 0x00007FF9753DB8E9 (_multiarray_umath.cp39-win_amd64.pyd) (located in PythonVM.exe): 0xC0000005: Access violation occurred while writing location 0x0000000000000008

NumPy/Python version information:

Numpy: 1.20.3
Python: 3.9.5
Platform: Win10
Compiler: Visual Studio 2019

1.20.3 3.9.5 (tags/v3.9.5:0a7dcbd, May 3 2021, 17:27:52) [MSC v.1928 64 bit (AMD64)]

[eric-wieser]

Numpy doesn't support being imported from multiple interpreters in a single process (even sequentially as you show there) as among other reasons it caches too many objects in static variables that can't be cleared.

Even if we fixed that, the python CAPI makes it quite challenging to implement things correctly with per-interpreter module state. An example is that there is no easy way for an tp_as_number.nb_add (aka __add__) method to obtain the relevant module state: PEP 573 only addresses regular methods, not slots.

[a2448825647]

Ok.....Thanks for your reply

[andyfaff]

This can be closed now, cp39 is no longer a target of active support.