diff --git a/modules/rostests/winetests/msi/custom.c b/modules/rostests/winetests/msi/custom.c
index 3a189efff68..f994ad4c18a 100644
--- a/modules/rostests/winetests/msi/custom.c
+++ b/modules/rostests/winetests/msi/custom.c
@@ -34,15 +34,15 @@
 
 static int todo_level, todo_do_loop;
 
-static void ok_(MSIHANDLE hinst, int todo, const char *file, int line, int condition, const char *msg, ...)
+static void WINAPIV ok_(MSIHANDLE hinst, int todo, const char *file, int line, int condition, const char *msg, ...)
 {
     static char buffer[2000];
     MSIHANDLE record;
-    va_list valist;
+    __ms_va_list valist;
 
-    va_start(valist, msg);
+    __ms_va_start(valist, msg);
     vsprintf(buffer, msg, valist);
-    va_end(valist);
+    __ms_va_end(valist);
 
     record = MsiCreateRecord(5);
     MsiRecordSetInteger(record, 1, todo);
diff --git a/modules/rostests/winetests/msi/db.c b/modules/rostests/winetests/msi/db.c
index 181301e1fe9..64edcb98c03 100644
--- a/modules/rostests/winetests/msi/db.c
+++ b/modules/rostests/winetests/msi/db.c
@@ -36,15 +36,15 @@ static const char *mstfile = "winetst-db.mst";
 static const WCHAR msifileW[] = {'w','i','n','e','t','e','s','t','-','d','b','.','m','s','i',0};
 static const WCHAR msifile2W[] = {'w','i','n','e','t','s','t','2','-','d','b','.','m','s','i',0};
 
-static void check_record_(int line, MSIHANDLE rec, UINT count, ...)
+static void WINAPIV check_record_(int line, MSIHANDLE rec, UINT count, ...)
 {
-    va_list args;
+    __ms_va_list args;
     UINT i;
 
     ok_(__FILE__, line)(count == MsiRecordGetFieldCount(rec),
             "expected %u fields, got %u\n", count, MsiRecordGetFieldCount(rec));
 
-    va_start(args, count);
+    __ms_va_start(args, count);
 
     for (i = 1; i <= count; ++i)
     {
@@ -57,7 +57,7 @@ static void check_record_(int line, MSIHANDLE rec, UINT count, ...)
                 "field %u: expected \"%s\", got \"%s\"\n", i, expect, buffer);
     }
 
-    va_end(args);
+    __ms_va_end(args);
 }
 #define check_record(rec, ...) check_record_(__LINE__, rec, __VA_ARGS__)