Event loop, non-blocking i/o

[Martin Junius <mj+gnome ml m-j-s net>]

Hi all!

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?

Regards,
Martin