diff --git a/rostests/winetests/msvcrtd/debug.c b/rostests/winetests/msvcrtd/debug.c
index fbfcdc5ea4d..71f6e4c3966 100644
--- a/rostests/winetests/msvcrtd/debug.c
+++ b/rostests/winetests/msvcrtd/debug.c
@@ -30,7 +30,7 @@
 
 /**********************************************************************/
 
-static void * (*pMSVCRTD_operator_new_dbg)(unsigned long, int, const char *, int) = NULL;
+static void * (__cdecl *pMSVCRTD_operator_new_dbg)(size_t, int, const char *, int) = NULL;
 
 /* Some exports are only available in later versions */
 #define SETNOFAIL(x,y) x = (void*)GetProcAddress(hModule,y)