diff --git a/programs/taskkill/taskkill.c b/programs/taskkill/taskkill.c
index b9dd1a5ebd5..6e4e1eb55ad 100644
--- a/programs/taskkill/taskkill.c
+++ b/programs/taskkill/taskkill.c
@@ -74,7 +74,7 @@ static int taskkill_vprintfW(const WCHAR *msg, __ms_va_list va_args)
     return count;
 }
 
-static int CDECL taskkill_printfW(const WCHAR *msg, ...)
+static int WINAPIV taskkill_printfW(const WCHAR *msg, ...)
 {
     __ms_va_list va_args;
     int len;
@@ -86,7 +86,7 @@ static int CDECL taskkill_printfW(const WCHAR *msg, ...)
     return len;
 }
 
-static int CDECL taskkill_message_printfW(int msg, ...)
+static int WINAPIV taskkill_message_printfW(int msg, ...)
 {
     __ms_va_list va_args;
     WCHAR msg_buffer[8192];