How can I print the type of a PyObject in an error message for an embedded Python script?

Question

My C++ code has this check in it:

if (1 != PyString_Check( key ))

and I'd like to get a "char*" of the type that it actually is in order to provide a more useful error message. Using the C API for Python, how would I do this?

Answer 1

PyTypeObject* type = key->ob_type;
const char* p = type->tp_name;
std::cout << "My type is " << p << std::endl;

Answer 2

As of Python 2.6, there is a macro, Py_TYPE, which should be used to access the type object of a PythonObject. You can then fetch the tp_name field which contains the fully-qualified name of the type. This means that the type of an object obj can be fetched as a C-string with:

const char* p = Py_TYPE(obj)->tp_name;