Re: updating gui while running a subroutine

[Jeffrey Ratcliffe <jeffrey ratcliffe gmail com>]

2009/1/30 Daniel Gaston <daniel gaston gmail com>:
> Is there something special I need to do with the piped open/fork to have it
> work for a subroutine within the same program code?

Below is what I have been doing - the forked code is here sub {sleep 10}.

Regards

Jeff

#!/usr/bin/perl

use warnings;
use strict;
use Gtk2 -init;
use Glib qw(TRUE FALSE);             # To get TRUE and FALSE
use POSIX;

my $window = Gtk2::Window->new;
$window -> signal_connect (delete_event => \&quit);
my $pbar = Gtk2::ProgressBar->new;
$pbar -> set_pulse_step(.1);
$window -> add($pbar);

my %helperTag;
$SIG{CHLD} = \&sig_child;

my $pid = start_process(sub {sleep 10});

Glib::Timeout->add (100, sub { if (defined $helperTag{$pid}) {
                                $pbar->pulse;
                                return TRUE;
                               }
                               else {
                                return FALSE;
                               } });

$window->show_all;
Gtk2->main;

# Process the exit of the child. If you were doing something useful,
# you might keep things like information about what data needs
# to be reloaded when a child process exits.

sub sig_child {
 my $pid = wait;
 if ($pid >= 0) {
warn("process $pid finished\n");
  delete $helperTag{$pid};
 }
}

sub start_process {
 my ( $process ) = @_;

 my $pid = fork();
 if ($pid) {

# We're still in the parent; note pid

  $helperTag{$pid} = $pid;
warn("Started process $pid\n");
  return $pid;
 }
 else {

# We're in the child. Do whatever processes we need to. We *must*
# exit this process with POSIX::_exit(...), because exit() would
# "clean up" open file handles, including our display connection,
# and merely returning from this subroutine in a separate process
# would *really* confuse things.
  $process->();
  POSIX::_exit(0);
 }
}


# We should clean up after ourselves so that we don't
# leave dead processes flying around.
sub quit {

# 15 = SIGTERM
 kill 15, $_ foreach (keys %helperTag);
 Gtk2->main_quit;
}