Re: X-windows: changing cursor from and AST ?

From: Bob Koehler (koehler_at_eisner.nospam.encompasserve.org)
Date: 04/07/05 

Date: 7 Apr 2005 09:12:05 -0500

In article <1112219312.6ff239a9957adc92052bbae698d71b5c@teranews>, JF Mezei <jfmezei.spamnot@teksavvy.com> writes:
>
> In an application which has a function which can either be instant or
> take a long time depending on size and type of contents, I'd like to be
> able to trigger a busy X-windows cursor only if it is to take a certain
> amount of time.
>
> Since the loop is outside the X-events main loop, and since it usually
> executes rather quickly, would it be possible (knowing that the loop
> itself does not generate any X-windows updates to the display) to have
> an AST triggered by a timer say one second after start of loop to change
> the cursor to a busy cursor ?
> (and possibly update cursor every second).

   X11 routines are not AST reentrant. We were able to call X11
   routines from AST in a system we did years ago only because no other
   X11 routines would be executing at the time. You probably instead
   should use XtAppAddInput (or whatever it's name is now) to add a VMS
   event flag as an input, set the event flag from the AST, and connect
   the event flag to a callback routine that updates the cursor.

   Don't use UNIX documentation for XtAppAddInput other than reading the
   line where it says that it's an OS-dependent routine.

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