Re: Event loop, non-blocking i/o

[DANIELLLANO <DANIELLLANO terra es>]

Martin Junius wrote:
> In my Gtk2 application gslish, see source at 
> http://cvs.sourceforge.net/viewcvs.py/slish/slish/perl/glade/gslish?rev=1.14&view=auto
> I'm running a computation and i/o extensive loop, which basically
> - computes PPM video frames
> - and outputs them to a "|ppmtoy4m|mpeg2enc" pipe.
>
> To make the user interface somewhat responsive I've implemented the 
> following:
> - At several points in the frame rendering functions I've added calls to
>   while (Gtk2->events_pending) {
>     Gtk2->main_iteration;
>   }
> - Furthermore I set the pipe file handle with fcntl to O_NONBLOCK and am 
> using syswrite for output to the pipe (this has the disadvantage of 
> syswrite returning after 4096 bytes written, requiring extra looping in 
> Perl).
> - And last but not least I'm using IO::Select to check with can_write 
> and a 0.050 s timeout on the pipe file handle.
>
> This all seems to work, but is not as fast as without the non-blocking 
> stuff. So I'm wondering: is there a better way to do these kind of 
> things in the world of Gtk2-Perl, maybe with some support from Glib?

I'd rather create another process/thread and do the computations there.
You can communicate the status to the gtk ui thread using a pipe or
something that works with glib main loop.

Daniel