I try to compile the example code from Python website https://docs.python.org/3/extending/embedding.html. Everything works fine except the following line:
pName = PyUnicode_DecodeFSDefault(argv[1]);
I have Python 3.6 installed on my MacOS El Captain. My make file looks like the following:
call_function: call_function.o
gcc -o call_function call_function.o -export-dynamic -L/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/config-3.6m-darwin -lpython3.6m -lpthread -lm -ldl -lutil
call_function.o:call_function.cpp
gcc -c call_function.cpp -I/Library/Frameworks/Python.framework/Versions/3.6/include/python3.6m
When I compile the C++ code, I get the following error:
gcc -c call_function.cpp -I/Library/Frameworks/Python.framework/Versions/3.6/include/python3.6m
call_function.cpp:16:13: error: use of undeclared identifier 'PyUnicode_DecodeFSDefault'
pName = PyUnicode_DecodeFSDefault(argv[1]);
^
1 error generated.
Does anyone know how to fix the above error? I would greatly appreciated for your help.
Here is the complete example code:
#include <Python/Python.h>
#include <Python/unicodeobject.h>
int main(int argc, char *argv[])
{
PyObject *pName, *pModule, *pDict, *pFunc;
PyObject *pArgs, *pValue;
int i;
if (argc < 3) {
fprintf(stderr,"Usage: call pythonfile funcname [args]\n");
return 1;
}
Py_Initialize();
pName = PyUnicode_DecodeFSDefault(argv[1]);
// pName = PyUnicode_FromString(argv[1]); <-- also gives me an error
/* Error checking of pName left out */
pModule = PyImport_Import(pName);
Py_DECREF(pName);
if (pModule != NULL) {
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);
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;
}
Py_Finalize();
return 0;
}