LIFO Win32 message loop?

Question

Is it possible to somehow cleverly use PostMessage, GetMessage, etc. to queue LIFO messages (assuming both the sender and the receiving message loop cooperate), or would I need to roll my own solution?

In case you're wondering about the use case, it's icon loading. You always want to load the most recently requested icons first. :)

score 2 · Accepted Answer · edited May 23 '17 at 10:09

2

No, you need to roll your own - the windows message queue has a maximum size, and if it ever gets full all sorts of things go badly wrong, from COM, DDE to user interaction.

Instead of using the thread queue, you should use a deque (or similar) protected by a critical section.

http://msdn.microsoft.com/en-us/library/windows/desktop/ms644944(v=vs.85).aspx

There is a limit of 10,000 posted messages per message queue. This limit should be sufficiently large. If your application exceeds the limit, it should be redesigned to avoid consuming so many system resources.

See also an example of what can go wrong:

0x80010100: System call failed" exception, ContextSwitchDeadlock

edited May 23 '17 at 10:09

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answered Jul 10 '12 at 15:27

Ben

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I don't have any windows or COM on this thread, so no worries if it gets full... Right? – user541686 Jul 10 '12 at 15:35
If you have no windows or COM why do you want to pump messages? – Ben Jul 10 '12 at 16:20
Just for my own stuff, message passing. – user541686 Jul 10 '12 at 16:24
OK, well my answer is "you may get unexpected behaviour if the queue gets full". – Ben Jul 10 '12 at 16:44

LIFO Win32 message loop?

1 Answers1