[Lazarus] Message Loop paused when no interaction with mouse?
mschnell at lumino.de
Wed Apr 20 16:22:31 CEST 2011
On 04/20/2011 03:51 PM, Bernd wrote:
> Are there any other ways under GTK2 (or xorg?) to send a message to a
> window that simulates user interaction?
Something is broken in the infra-structure of the Event queuing
mechanism with GTK2 and this can hit in multiple issues. As long as
TApplication.QueuAsyncCall() (that supposedly uses the basics of the
mechanism) does not work reliably, you can't trust the event scheduling
For your own Events you could uses the Windowish "PostMessage" interface
to access a "procedure...Message()". Same seems to work with the current
Last time I checked, TApplication.QueuAsyncCall() did work with the (now
unsupported) gtk ("1") Widgest Type.
> What exactly does the TTimer do when it fires its event? The TTimer
> seems to have the power to wake up the GUI, maybe I can do the same
AFAIK the TTimer is just a GUI element direct provided by GTK itself, so
the LCL does not need to actively stuff events in the queue and wake the
Stuffing events in the queue seems always to be workable but waking the
GUI thread does not seem to work reliably with some Widget Types, so
manually waking it by moving the mouse or something like this does make
the GUI thread handle all scheduled events. My testing program shows
that a TTimer doing nothing indeed wakes the GUI thread and makes it
handle the queued events. Also doing a "PostMessage" to an empty
"procedure...Message;" seems wake the GUI Thread and makes it handle
the queued events.
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