cannot import python pkgs in C++

Question

I wanna build a C++ program to run python Scripts which imports numpy, my python version is anaconda, I run the program but it reports "No module named numpy". Here is the code

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

int main(int argc, char *argv[])
{
    if (argc < 1) {
        fprintf(stderr, "Usage: call pythonfile funcname [args]\n");
        return 1;
    }
    wchar_t *pName = Py_DecodeLocale(argv[0], NULL);
    if (pName == NULL) {
        fprintf(stderr, "Fatal error: cannot decode argv[0]\n");
        exit(1);
    }
    // std::cout << pName << std::endl;
    Py_SetProgramName(pName);
    Py_Initialize();
    PyRun_SimpleString("from time import time,ctime\n"
        "print('Today is', ctime(time()))\n");
    PyRun_SimpleString("import sys, os");
    PyRun_SimpleString("print(os.getcwd())");
    PyRun_SimpleString("sys.path.append(os.getcwd())");
    PyRun_SimpleString("sys.path.append(\"D:/repos/cppCallPython/x64/Release\")");
    PyRun_SimpleString("print(sys.path)");
    // PyRun_SimpleString("import numpy");
    PyObject *moduleName, *pModule;
    moduleName = PyUnicode_DecodeFSDefault("interface");
    // moduleName = PyUnicode_DecodeFSDefault(argv[1]);
    pModule = PyImport_Import(moduleName);
    if (pModule == NULL) {
        PyErr_Print();
        fprintf(stderr, "Fails to import the module.\n");
    }
    Py_DECREF(moduleName);
    if (Py_FinalizeEx() < 0) {
        exit(120);
    }
    PyMem_RawFree(pName);
    system("pause");
    return 0;
}

> Today is Mon Oct 29 16:32:38 2018 D:\repos\cppCallPython\cppCallPython ['C:\Users\Bryan Zoe\Anaconda3\python36.zip', 'C:\Users\Bryan Zoe\Anaconda3\Lib', 'C:\Users\Bryan Zoe\Anaconda3\DLLs', 'C:\Program Files\Python36\Lib', 'C:\Program Files\Python36\DLLs', 'D:\repos\cppCallPython\x64\Release', 'C:\Program Files\Python36', 'C:\Program Files\Python36\lib\site-packages', 'D:\repos\cppCallPython\cppCallPython', 'D:/repos/cppCallPython/x64/Release'] Traceback (most recent call last): File "D:\repos\cppCallPython\x64\Release\interface.py", line 1, in import numpy as np ModuleNotFoundError: No module named 'numpy' Fails to import the module.

interface.py is located in 'D:/repos/cppCallPython/x64/Release'. It seems the python interpreter is a pure interpreter, the code creates a new python virtualenv. I don't know how to fix it. Here is code of interface.py

import numpy as np
zeros = np.zeros((3, 3))
print("Succeeds to call python scripts")
print(zeros)

it works fine in the power shell

Does that Python code work if you run it in an interactive shell from the same working directory as the compiled executable? — Ulrich Eckhardt, Oct 29 '18 at 08:51

score 1 · Accepted Answer · answered Oct 29 '18 at 09:15

1

check you code, the python build-in package is work OK, such as the time and os package. The numpy is the third package, it's not wotk, so you need like the python library install folder into C++ program linker additional library.

In VS, is setting path may like this Project > Properties > Configuration Properties > Linker > General > Additional Library Directory

please check.

answered Oct 29 '18 at 09:15

youDaily

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Thanks for you advice, I check the sys.path and find the program link the wrong site-packages library folder. I add "C:\Users\Bryan Zoe\Anaconda3\Lib\site-packages" to sys.path and it works. – BIT_Bang Oct 30 '18 at 02:08

cannot import python pkgs in C++

1 Answers1