🚀 go-pugleaf

"Kris" <ks@ks.com> wrote in message 
news:47bc8219$1@newsgroups.borland.com...

> I do have another question though. My app is loaded during windows startup 
> in the system tray (and does not show its main window). Most of the time 
> this works just fine, but occasionally the app gets loaded but no system 
> tray icon is created. It's hard to reproduce, but it does happen from time 
> to time.

I just noticed this at the bottom of the Shell_NotifyIcon() documentation:

    Shell_NotifyIcon Function
    http://msdn2.microsoft.com/en-us/library/bb762159.aspx

    Handling Shell_NotifyIcon failure

    Shell_NotifyIcon will often fail when called during Windows startup (for 
instance, if your application is listed in 
HKLM\Software\Microsoft\Windows\CurrentVersion\Run. This appears to be 
because the system is busy starting applications. The failure is more common 
on low-spec computers or computers with some brands of antivirus software 
installed, which seem to be very intensive at startup.

    Unfortunately, you cannot rely on the error code returned by 
GetLastError. When Shell_NotifyIcon returns false, some of the common errors 
returned by GetLastError are:

    ERROR_FILE_NOT_FOUND (2)

    ERROR_TIMEOUT (1460)

    ERROR_SUCCESS (0)

    The most appropriate response to any error returned by Shell_NotifyIcon 
is to sleep for a period of time and retry.

    An explanation of why the error code may differ has been made by Paul 
Baker, paraphrased from 
http://groups.google.com/group/microsoft.public.platformsdk.shell/msg/59235b293cbf5dfa 
and 
http://groups.google.com/group/microsoft.public.platformsdk.shell/msg/73973287f15c03fc:

    Shell_NotifyIcon actually calls SetLastError(0) initially. After that, 
basically it uses FindWindow to find the tray notification window. If this 
fails, it will typically return ERROR_FILE_NOT_FOUND. Otherwise it sends a 
WM_COPYDATA message to the tray notification window, using 
SendMessageTimeout with a timeout of only 4 seconds. If that message returns 
zero, then Shell_NotifyIcon will fail with GetLastError returning zero.


Gambit