diff --git a/Modules/_ctypes/callproc.c b/Modules/_ctypes/callproc.c
index 01ba8a0..7f7d641 100644
--- a/Modules/_ctypes/callproc.c
+++ b/Modules/_ctypes/callproc.c
@@ -221,7 +221,7 @@
 	n = FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
 			  NULL,
 			  code,
-			  MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
+			  MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), /* Default language */
 			  (LPTSTR) &lpMsgBuf,
 			  0,
 			  NULL);