C-API for Python 3 - Get String from Object

[mga010]

I try to read a string from a python object in the C-API but seem to be incapable to find the documentation on how to do that properly in Python 3. The problem could be Unicode or any other issue I am not aware of. I had a solution for Python 2.

So what is wrong with the following code? It fails in the last step with out==0.

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#include <stdio.h> #include <Python.h>   const char* pystart = "t = \"test\"";   int main() {     printf("Test Programm for Python 3.8\n");       Py_Initialize();       PyObject* pModule = PyImport_AddModule("__main__"); //create main module     if (!pModule)     {         printf("Could not create main module in Python.");         return 0;     }       if (PyRun_SimpleString(pystart) == -1)     {         printf("Could not run pystart.");         return 0;     }       PyObject* t = PyObject_GetAttrString(pModule, "t");     if (!t)     {         printf("Could not get t.");         return 0;     }     char* out = PyBytes_AsString(t);     if (!out)     {         printf("Could not get the string.");         return 0;     }     printf(out);       return 1; }

[Gribouillis]

With your code, the object t will not be a bytes object but a str object, that's why PyBytes_AsString fails and return NULL. You could replace pystart with

1	pystart = "t = b\"test\"";

[mga010]

With your code, the object t will not be a bytes object but a str object, that's why PyBytes_AsString fails and return NULL. You could replace pystart with

1	pystart = "t = b\"test\"";

That does indeed work, I tried it. Unfortunately, I cannot use this in the program I am developing. I need to get the content of a Python string via C.

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I found the solution now. You have to actively convert with PyUnicode_AsEncodedString before applying PyBytes_AsString. I finally found that in the docs.