[PATCH?] Finally found a solution to serial port writes

[Geoffrey Hausheer]

The following patch is probably wrong, but it fixes my problem with
WriteFile failing when writing to a COM port.  The problem appears to be
that NtWaitForSingleObject sends a count of '1' which results in the
wine_server_call in NTDLL_wait_for_multiple_objects returning
'STATUS_USER_APC' which aborts the execution before 'call_apcs' gets
called (which actually does the write).

calling 'NTDLL_wait_for_multiple_objects' with count = 0 allows the
'call_apcs' function to get called, and TzMax50 actually works perfectly
(along with my nasty hack to allow the menus to work)

as a reminder, the COM port is opened in non-overlapped mode, and all
timeouts are set to 0.

(I didn't submit this to wine-patches, since i'm not at all sure it is
generally correct)

I can also try to write a test-case that shows this works (sort of...I
can test that WriteFile returns the right result, but not that data was
actually written on the serial port.  I know of no way to do that without
external hardware).  I don't know how to make it general enough though
(what to do when there is no COM port attached to the machine?)

.Geoff

--- orig/dlls/ntdll/file.c
+++ mod/dlls/ntdll/file.c
@@ -585,7 +585,7 @@
         ret = register_new_async(&ovp->async);
         if (ret != STATUS_SUCCESS)
             return ret;
-        if (flags & FD_FLAG_TIMEOUT)
+        if (hEvent != NULL && flags & FD_FLAG_TIMEOUT)
         {
             NtWaitForSingleObject(hEvent, TRUE, NULL);
             NtClose(hEvent);