Daniel Davidson said:
> This may be a problem with my understanding of perl and not with GTK,
> but here goes anyway.
Actually, it's a subtle interaction of various pieces.
> $tag = Gtk2::Helper->add_watch(fileno($fractread), 'in', \&setstatus);
> sub setstatus{
> $progressbar->set_text(<$progread>);
> $progressbar->set_fraction(<$fractread>);
Note blocking buffered reads. See below.
> Gtk2->main_iteration while Gtk2->events_pending;
> print "in status\n";
Watch out -- you're implicitly returning nonzero here because the print is
your block's last statement. HOwever, the return value of the callback is
supposed to be a boolean indicating whether the callback is to stay installed.
> }
>
> And finally in the child process I print to the pipe.
> print $fractwrite $count/$totaldays;
> print $statuswrite "Populating Database $count of $totaldays
> ".int($count/$totaldays*100)."%";
Note lack of a newline to flush the output buffer.
> Only problem is that nothing ever happens, even though I know the child
> process is running. Any ideas what I am screwing up?
Don't use buffered IO and blocking reads with IO watches. The IO watch fires
when *real* input arrives, and using buffered IO with that messes with your
mind. Also, the <> operator will attempt to read up to a $/, and will block
until it does. By default, $/ is "\n", and you're not writing a "\n" to your
output stream.
So, your callback is being invoked once, and is hanging on the read, waiting
for a newline to show up.
Set $|=1 (autoflush) in the child, and use sysread() in your IO watch
callbacks. By the way, when using sysread(), you must be prepared to handle
partial line reads.
This is another FAQ; i believe the solution in the FAQ contains misleading
code. Any volunteers to update that?
--
muppet <scott at asofyet dot org>
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