Obtain current Python call stack from within SWIG wrapped C++ function

Question

if I call a SWIG-wrapped C/C++ function from Python, is it possible to obtain the current call stack? I would like something similar to the result of ''.join(traceback.format_stack()), but I don't want to pass this from Python to my C/C++ functions because I don't always need it. So I would like to obtain it on the fly and print it if something wrong happens on my C/C++ side.

Answer 1

I figured out a solution following this post, although I still prefer more natural ways of getting the same thing if there is any.

// This is similar to the python code:
//   def GetScriptingLanguageCallStack():
//     import traceback
//     return ''.join(traceback.format_stack())
string GetScriptingLanguageCallStack() {
  string result;

  PyObject* module_name = PyString_FromString("traceback");
  PyObject* pyth_module = PyImport_Import(module_name);
  Py_DECREF(module_name);

  if (pyth_module != nullptr) {
    PyObject* pyth_func = PyObject_GetAttrString(pyth_module, "format_stack");
    if (pyth_func != nullptr) {
      if (PyCallable_Check(pyth_func)) {
        PyObject* pyth_val = PyObject_CallFunctionObjArgs(pyth_func, 0);
        if (pyth_val != nullptr) {
          if (PyList_Check(pyth_val)) {
            const int size = PyList_GET_SIZE(pyth_val);
            for (int i = 0; i < size; ++i) {
              PyObject* pyth_line = PyList_GET_ITEM(pyth_val, i);
              result += PyString_AsString(pyth_line);
            }
          }
          Py_DECREF(pyth_val);
        }
      }
      Py_DECREF(pyth_func);
    }
    Py_DECREF(pyth_module);
  }
  return result;
}

By the way, I do not prefer the approach in the linked post which uses frame object, because the line number given is not pointing to the exact line which makes the further function calls, but only on the line containing the function name.