[fpc-pascal] fpSelect() with very small timeout?

[Martin Schreiber]

On Monday 20 October 2008 10.36:48 Graeme Geldenhuys wrote:
> On Mon, Oct 20, 2008 at 10:19 AM, Martin Schreiber <fpmse at bluewin.ch> wrote:
> > [...]
> > You could send a wakeup message to the X event queue if a widget has been
> > invalidated instead of polling. See MSEgui lib/common/msegui.pas
> > tguiapplication.invalidated and the postevent infrastructure for an
> > example.
>
> Thanks Martin.  I take it, your method would be a bit more efficient
> than polling? Or wouldn't it make much difference because the event
> loop keeps looping anyway?
>
The MSEgui main event loop waits on a poll() call for X messages. There is a 
emergency timeout of one second because the new xcb library seems to have a 
problem by sometimes not to deliver client messages in time.

> For example: Using the wakeup event, it will simply break out of the
> message handling a bit quicker. "if XPending(display) > 0" would have
> a "else" part where it fires the OnIdle event and then breaks out.
> Skipping (or making redundant) the "if needToWait ..." block of code.
>

No, the purpose of the wakeup message is to terminate the poll() call. 
Updating the widgets and call of OnIdle will be done before poll() is called 
again.

Martin