winmm: A NULL CALLBACK_FUNCTION is acceptable since w2k.
diff --git a/dlls/winmm/driver.c b/dlls/winmm/driver.c
index 48152ab..23338d2 100644
--- a/dlls/winmm/driver.c
+++ b/dlls/winmm/driver.c
@@ -543,8 +543,6 @@
switch (uFlags & DCB_TYPEMASK) {
case DCB_NULL:
TRACE("Null !\n");
- if (dwCallBack)
- WARN("uFlags=%04X has null DCB value, but dwCallBack=%08lX is not null !\n", uFlags, dwCallBack);
break;
case DCB_WINDOW:
TRACE("Window(%04lX) handle=%p!\n", dwCallBack, hDev);
@@ -556,7 +554,8 @@
break;
case DCB_FUNCTION:
TRACE("Function (32 bit) !\n");
- ((LPDRVCALLBACK)dwCallBack)(hDev, wMsg, dwUser, dwParam1, dwParam2);
+ if (dwCallBack)
+ ((LPDRVCALLBACK)dwCallBack)(hDev, wMsg, dwUser, dwParam1, dwParam2);
break;
case DCB_EVENT:
TRACE("Event(%08lx) !\n", dwCallBack);