bpo-40170: Convert PyObject_IS_GC() macro to a function (GH-19464)
diff --git a/Include/cpython/objimpl.h b/Include/cpython/objimpl.h
index 6634f29..b835936 100644
--- a/Include/cpython/objimpl.h
+++ b/Include/cpython/objimpl.h
@@ -120,10 +120,9 @@
PyAPI_FUNC(Py_ssize_t) _PyGC_CollectIfEnabled(void);
-/* Test if an object has a GC head */
-#define PyObject_IS_GC(o) \
- (PyType_IS_GC(Py_TYPE(o)) \
- && (Py_TYPE(o)->tp_is_gc == NULL || Py_TYPE(o)->tp_is_gc(o)))
+/* Test if an object implements the garbage collector protocol */
+PyAPI_FUNC(int) PyObject_IS_GC(PyObject *obj);
+
/* Code built with Py_BUILD_CORE must include pycore_gc.h instead which
defines a different _PyGC_FINALIZED() macro. */