C extension module doesn't throw exception after setting error indicator through PyErr_SetString()

[rahul]

I am implementing a C extension module, during this I saw that when I set the global error indicator and error message through PyErr_SetString() API and return false.

But it doesn't throw any error when I tried to check the error through sys.exc_info() then it returns (NULL, NULL, NULL) tuple. 

When I return NULL through the C extension module's function then it works correctly and throws the exception as expected.

The skeleton looks like:

static PyObject* check(PyObject* sef, PyObject* args)
{
        PyObject* input = NULL;
        if (!PyArg_ParseTuple(args, "O", &input)){
             return NULL;
        }
        .....
        .....
        PyErr_SetString(PyExc_Exception, "Throwing Error through check function");
        Py_RETURN_FALSE;
}

Any idea on why this is happening? Any help will be appreciated.

Thanks,
Rahul