Re: Machile level exception
- Posted by CChris Jan 23, 2009
- 1086 views
When Windows sends a mesage o a window, it may expect a reply, depending on the message.
returnValue() forces such a reply from the user defined handlers, before the default message processing for the window kicks in. For some messages, the only thing that matters is zero vs nonzero. For other messages, it is a different story. You have to search MSDN for the meaning of the return value of a particular message, or use some other docs.
doEvents() is hardly related, since it forces processing pending messages before returning to caller. You'll use this to refresh a window you repaint inside a handler, for instance. The 0 usually passed to it is Screen actually. You could use a control id to check messages pending for this control specifically.
CChris
No way to edit a post... The above is slightly too vague.
doEvents() checks whether there is a message pending. If so, it triggers the processing of this partiular message and returns, regardless of there being more in the queue. If no message is pending, procedure returns without waiting. And I forgot to mention that the task scheduler is called after a message is processed in this way.
CChris
