diff --git a/PC/pyconfig.h b/PC/pyconfig.h
index 592b487..00a65b2 100644
--- a/PC/pyconfig.h
+++ b/PC/pyconfig.h
@@ -165,11 +165,11 @@ WIN32 is still required for the locale module.
 
 /* Define like size_t, omitting the "unsigned" */
 #ifdef MS_WIN64
-typedef __int64 ssize_t;
+typedef __int64 Py_ssize_t;
 #else
-typedef _W64 int ssize_t;
+typedef _W64 int Py_ssize_t;
 #endif
-#define HAVE_SSIZE_T 1
+#define HAVE_PY_SSIZE_T 1
 
 #if defined(MS_WIN32) && !defined(MS_WIN64)
 #if defined(_M_IX86)