无法从linux，c ++执行“ my_script” python脚本的“ main（filename）”功能； pModule = PyImport_Import（pName）; 返回null

Question

trying to call main(filename) function of my_script.py from main() of Linux,c++.

For pName = PyUnicode_DecodeFSDefault(argv[1]); pName is not NULL, but next call pModule = PyImport_Import(pName); pModule is NULL.

The main function of my_script will take filename of image as parameter and return a string containing the name of vegetable. Here pModule = PyImport_Import(pName); pModule returns null.

I tried pwd got /home/sandeep/Downloads/VegeTable-master/VegeTable/image_recognition

export PYTHONPATH=/home/sandeep/Downloads/VegeTable-master/VegeTable/image_recognition but still pModule is NULL

int main(int argc, char* argv[])
{

    PyObject *pName, *pModule, *pFunc;
    PyObject *pArgs, *pValue, *syspath;
    int i;
    char * str = get_current_dir_name();
    char* path, *eximpath = "/etc/exim";
    cout<<"str="<<str<<endl;
    if (argc < 3) {
        fprintf(stderr,"Usage: call pythonfile funcname [args]\n");
        return 1;
    }
    wchar_t *program = Py_DecodeLocale(argv[0], NULL);
    if (program == NULL) {
        fprintf(stderr, "Fatal error: cannot decode argv[0]\n");
        exit(1);
    }

    Py_SetProgramName(program);
    Py_Initialize();


    system("echo $PYTHONPATH");
    pName = PyUnicode_DecodeFSDefault(argv[1]);
    /* Error checking of pName left out */

    if(pName)
       cout<<"OK:"<<endl;

    pModule = PyImport_Import(pName);
    Py_DECREF(pName);

    if(pModule) cout<<"success"<<endl;

     if (pModule != NULL)
  {
             cout<<"success"<<endl;
         pFunc = PyObject_GetAttrString(pModule, argv[2]);
         /* pFunc is a new reference */

         if (pFunc && PyCallable_Check(pFunc))
         {
             pArgs = PyTuple_New(argc - 3);
             for (i = 0; i < argc - 3; ++i)
             {
                 pValue = PyLong_FromLong(atoi(argv[i + 3]));
                 if (!pValue)
                 {
                    Py_DECREF(pArgs);
                    Py_DECREF(pModule);
                    fprintf(stderr, "Cannot convert argument\n");
                    return 1;
                 }
                 /* pValue reference stolen here: */
                 PyTuple_SetItem(pArgs, i, pValue);
             }
             pValue = PyObject_CallObject(pFunc, pArgs);
             cout<<"success"<<endl;
             Py_DECREF(pArgs);
             if (pValue != NULL)
             {
                 printf("Result of call: %ld\n", PyLong_AsLong(pValue));
                 Py_DECREF(pValue);
             }
             else
             {
                Py_DECREF(pFunc);
                Py_DECREF(pModule);
                PyErr_Print();
                fprintf(stderr,"Call failed\n");
return 1;
             }

         }
         else
         {
            if (PyErr_Occurred())
                PyErr_Print();
            fprintf(stderr, "Cannot find function \"%s\"\n", argv[2]);
         }
         Py_XDECREF(pFunc);
         Py_DECREF(pModule);

     }
     else
     {
        PyErr_Print();
        fprintf(stderr, "Failed to load \"%s\"\n", argv[1]);
        return 1;
    }
    if (Py_FinalizeEx() < 0)
    {
        return 120;
    }
}

output-
str=/home/sandeep/Downloads/VegeTable-master/VegeTable/image_recognition
/home/sandeep/Downloads/VegeTable-master/VegeTable/image_recognition
OK:
  File "/home/sandeep/Downloads/VegeTable-master/VegeTable/image_recognition/my_script.py", line 135
    return ('unknown')
                     ^
TabError: inconsistent use of tabs and spaces in indentation
Failed to load "my_script"

for running code I am using ./pyembed my_script main download.jpeg

I wrote a new function and 2 script files from scratch. Contents of both the script files are same. But it runs in 1 and gives error in other. an.py->

#!/usr/bin/python

def fun(name):
    return 4

myscript.py->

#!/usr/bin/python

#import cv2
#import numpy as np

def fun(name):
   return 4

contents of embedpy.c

int main(int argc, char* argv[])
{

    wchar_t* program;
    PyObject *pName, *pModule, *pFunc;
    PyObject *pArgs, *pValue, *syspath;
    int i;

    if(argc<3)
    {
        cerr<<"Usage: call pythonfile funcname [args]\n"<<endl;
        return 1;
    }

    program = Py_DecodeLocale(argv[0],NULL);

    Py_SetProgramName(program);
    Py_Initialize();


    pName = PyUnicode_DecodeFSDefault(argv[1]);

    if(!pName)
    {
        cerr<<"error in pName"<<endl;

        return 1;
    }


    pModule = PyImport_Import(pName);
    Py_DECREF(pName);

    if(!pModule)
    {
        PyErr_Print();
        cerr<<"error in pModule"<<endl;

        return 1;
    }

    pFunc = PyObject_GetAttrString(pModule, argv[2]);

    if(!pFunc || !PyCallable_Check(pFunc))
    {
        if (PyErr_Occurred())
                PyErr_Print();
        cerr<<"can not find function"<<argv[2]<<endl;

        return 1;
    }

    pArgs = PyTuple_New(argc - 3);
    for(int i = 0; i < argc-3; i++)
    {
        pValue = PyLong_FromLong(atoi(argv[i + 3]));

        if(!pValue)
        {
            Py_DECREF(pArgs);
            Py_DECREF(pModule);

            cerr<<"can not convert argument"<<endl;

            return 1;
        }

        PyTuple_SetItem(pArgs, i, pValue);
    }


    }

    pValue = PyObject_CallObject(pFunc, pArgs);
    Py_DECREF(pArgs);

    if(!pValue)
    {
        Py_DECREF(pFunc);
        Py_DECREF(pModule);

        PyErr_Print();
        cerr<<"function call failed"<<endl;

        return 1;
    }

    cout<<"Result of Call = "<<PyLong_AsLong(pValue)<<endl;
    Py_DECREF(pValue);


    if (Py_FinalizeEx() < 0)
    {
        return 120;
    }

}

I am running with

./embedpy an fun download.jpeg

and

./embedpy myscript fun download.jpeg

in 1st case error - ModuleNotFoundError: No module named 'an' error in pModule

in 2nd case no error Result of Call = 4

My real problem(practical) is I am unable to run

./embedpy my_script main download.jpeg

error- ModuleNotFoundError: No module named 'my_script' error in pModule

ls -l gives
-rw-r--r-- 1 sandeep sandeep       47 Jul 19 14:31 an.py
-rwxrwxrwx 1 sandeep sandeep     3947 Jul 19 13:50 my_script.py
-rw-r--r-- 1 sandeep sandeep       79 Jul 19 14:31 myscript.py
-rwxr-xr-x 1 sandeep sandeep    13816 Jul 19 13:59 embedpy
-rw-r--r-- 1 sandeep sandeep     1804 Jul 19 13:54 embedpy.cpp
-rw-r--r-- 1 sandeep sandeep       79 Jul 19 14:53 script2.py

I copied using

cp myscript.py script2.py

but

./embedpy script2 fun download.jpeg 

ModuleNotFoundError: No module named 'script2' error in pModule

and

./embedpy myscript fun download.jpeg

Result of Call = 4

Strange-> i did

export PYTHONPATH=/home/sandeep/Downloads/VegeTable-master/VegeTable/image_recognition

and

./embedpy an fun download.jpeg
./embedpy myscript fun download.jpeg
./embedpy script2 fun download.jpeg

give

Result of Call = 4

./embedpy my_script main download.jpeg

gives File "/home/sandeep/Downloads/VegeTable-master/VegeTable/image_recognition/my_script.py", line 136 return ('unknown') ^ TabError: inconsistent use of tabs and spaces in indentation

error in pModule

I am trying to include elements 1 by 1 from "my_script.py" to "an.py" I included 2 imports and it gives error

an.py->

!/usr/bin/python

import cv2
import numpy as np

def fun(name):
    return 4

./embedpy an fun download.jpeg

gives Traceback (most recent call last): File "/home/sandeep/Downloads/VegeTable-master/VegeTable/image_recognition/an.py", line 3, in import cv2 ModuleNotFoundError: No module named 'cv2' error in pModule

any guess- what is wrong, the python file executes ok independently I typed in console "conda update anaconda-navigator" conda: command not found

Answer 1

The program you have written is in C++ and if you add the file extension as my_script.py, it won't work. Try changing the file extension to my_script.cpp. The error itself is regarding the indentation and use of tabs, which is required in python instead of using curly brackets. And include the packages as headers in the program for you to use the packages.