python - Pass std::string into PyObject_CallFunction -

when run presult = pyobject_callfunction(pfunc, "s", &"string"), python script returns correct string. but, if try run this:

std::string passedstring = "string"; presult = pyobject_callfunction(pfunc, "s", &passedstring) 

then convert presult std::string, <null> when print it. here (probably) complete code returns <null>:

c++ code:

#include <python.h> #include <string> #include <iostream>  int main() {     pyobject *pname, *pmodule, *pdict, *pfunc;      // set pythonpath working directory     setenv("pythonpath",".",1); //this doesn't     setenv("pythondontwritebytecode", " ", 1);      // initialize python interpreter     py_initialize();      // build name object     pname = pyunicode_fromstring((char*)"string");     // load module object     pmodule = pyimport_import(pname);     // pdict borrowed reference     pdict = pymodule_getdict(pmodule);     // pfunc borrowed reference     pfunc = pydict_getitemstring(pdict, (char*)"getstring");      if (pfunc != null)     {         if (pycallable_check(pfunc))         {             pyobject *presult;              std::string passedstring = "string";             presult = pyobject_callfunction(pfunc, "s", &passedstring);              pyobject* presultstr = pyobject_repr(presult);              std::string returnedstring = pyunicode_asutf8(presultstr);             std::cout << returnedstring << std::endl;              py_decref(presult);             py_decref(presultstr);         }         else {pyerr_print();}     }     else {std::cout << "pfunc null!" << std::endl;}      // clean     py_decref(pfunc);     py_decref(pdict);     py_decref(pmodule);     py_decref(pname);      // finish python interpreter     py_finalize(); } 

python script (string.py):

def getstring(returnstring):         return returnstring 

i'm on ubuntu (linux) , i'm using python 3.4

you should pass c-style string pyobject_callfunction code work. in order c-string std::string, use c_str() method. following line:

presult = pyobject_callfunction(pfunc, "s", &passedstring); 

should this:

presult = pyobject_callfunction(pfunc, "s", passedstring.c_str());