C++ embedded python asynchronously

Question

I have some code where multiple tasks run at once. Some tasks may take a few ms, others will take some seconds. For this I'm using std::async and std::future to run these tasks asynchronously. Everything was working fine untill I added some code to run Python functions within C++. I run following code asynchronously.

This code will start the task if it's not running.

#include <future>
#include <Python.h>

struct Tasks {
    future<void> myTask;
} tasks;

struct Python {
    PyObject *pName, *pModule, *pFunc, *pArgs, *pValue;
} python;

...

void MyFunction(long var1){
    Py_Initialize();
    python.pName = PyUnicode_FromString((char*)"filename");
    python.pModule = PyImport_Import(python.pName);
    // ERROR IS OCCURING HERE
    python.pFunc = PyObject_GetAttrString(python.pModule, (char*)"python_function");
    python.pArgs = PyTuple_Pack(1, PyLong_FromLong(var1));
    python.pValue = PyObject_CallObject(python.pFunc, python.pArgs);
    auto result = _PyUnicode_AsString(python.pValue);
    std::cout << result << std::endl;
    Py_Finalize();
}

...

void CallTask(long var1){
    if (tasks.myTask.valid() && tasks.myTask.wait_for(1ms) != future_status::ready) {
        cout << "Cannot execute command, still executing.\n";
    } else {
        tasks.myTask= async(launch::async, MyFunction, var1);
    }
}

The python function I'm calling can take up to 2 minutes to return a result.

The error I get is:

terminate called after throwing an instance of 'std::system_error'
  what():  Resource deadlock avoided

What could cause this error? If you need more information, please leave a comment.

Answer 1

这是通过设置环境变量“PYTHONPATH”解决的

setenv("PYTHONPATH", ".", 1);