--- mstools/samples/polydraw/polydraw.h	2018/08/09 18:20:38	1.1.1.1
+++ mstools/samples/polydraw/polydraw.h	2018/08/09 18:21:22	1.1.1.2
@@ -2,7 +2,7 @@
 
 
 /* function prototypes for the window procedures. */
-LRESULT MainWndProc(HWND, UINT, WPARAM, LPARAM);
+LRESULT CALLBACK MainWndProc(HWND, UINT, WPARAM, LPARAM);
 
 #define MAXPOINTS  16
 #define NONE     -1