c++ call python script failed, when the called scipt import another script

Question

I want to call a python scipt sayhello.py which located at D:/semantic_segmentation/scripts in my c++ program, here is my c++ code:

Py_Initialize();
PyRun_SimpleString("import sys");
PyRun_SimpleString("sys.path.append('D:/semantic_segmentation/scripts')");
PyObject* pModule = PyImport_ImportModule("sayhello");

the code of sayhello.py is:

import sys
sys.path.append("..")
import a

def _sayhello(x):
    print('hello')
    return x

_sayhello(1)

When I run my C++ program the function PyImport_ImportModule returns NULL, but when I run sayhello.py with python -m sayhello.py directly it works fine. How can i fix this?

edit: I found the problem is in the following code:

sys.path.append("..")
import a

the c++ program doesn't work when i import other script in sayhello.py. But when i move a.py to the same path with sayhello.py, and import a.py only with import a, my c++ program works. So my question is, how can i make my c++ program calling python script work, when the called script calls another script which located in other path?

it is another script a.py, which is located at *D:/semantic_segmentation*. If i remove ```import a```, i can run my c++ praogram successfully. It turns out that when i import other scripts in *sayhello.py*, my c++ program doesn't work. — xiaojifeng, Jul 28 '20 at 09:22

score 0 · Accepted Answer · answered Jul 28 '20 at 10:14

It looks like your python code assumes the current working directory of the process is the D:/semantic_segmentation/scripts directory, which is not necessarily the case.

Here are two solutions:

change the working directory of your c++ program with chdir or the windows equivalent, or
change the python code to compute an absolute path starting from the script file instead of the current working directory. See this answer.

c++ call python script failed, when the called scipt import another script

1 Answers1