cpython/Modules/_testlimitedcapi/testcapi_long.h

/* Poor-man's template.  Macros used:
   TESTNAME     name of the test (like test_long_api_inner)
   TYPENAME     the signed type (like long)
   F_S_TO_PY    convert signed to pylong; TYPENAME -> PyObject*
   F_PY_TO_S    convert pylong to signed; PyObject* -> TYPENAME
   F_U_TO_PY    convert unsigned to pylong; unsigned TYPENAME -> PyObject*
   F_PY_TO_U    convert pylong to unsigned; PyObject* -> unsigned TYPENAME
*/

static PyObject *
TESTNAME(PyObject *error(const char*))
{ … }