--- mstools/h/winperf.h	2018/08/09 18:22:57	1.1.1.3
+++ mstools/h/winperf.h	2018/08/09 18:25:19	1.1.1.4
@@ -511,9 +511,9 @@ typedef struct _PERF_COUNTER_BLOCK {
 //
 //  function typedefs for extensible counter function prototypes
 //
-typedef DWORD (PM_OPEN_PROC) (LPWSTR);
-typedef DWORD (PM_COLLECT_PROC) (LPWSTR, LPVOID *, LPDWORD, LPDWORD);
-typedef DWORD (PM_CLOSE_PROC) ();
+typedef DWORD (APIENTRY PM_OPEN_PROC) (LPWSTR);
+typedef DWORD (APIENTRY PM_COLLECT_PROC) (LPWSTR, LPVOID *, LPDWORD, LPDWORD);
+typedef DWORD (APIENTRY PM_CLOSE_PROC) (void);
 
 #endif // _WINPERF_