Perl/Tk is not threads-friendly. Its not exactly threads-hostile, but you need to make sure you run Perl/Tk in its own thread, and don't spawn any new threads from the same thread as Perl/Tk runs in.

That means you can't just rely on MainLoop magically stepping aside to check on your other threads, nor can you fiddle with Tk's structures from an external thread. You'll need to add a repeat timer event before calling MainLoop, and use queues to pass commands/data back and forth.

Here's some (untested) code snippets to get you going. 

#!/usr/bin/perl -w  
use threads;
use Thread::Queue;
use Tk;
use strict;

my $cmdq = Thread::Queue->new();
my $respq = Thread::Queue->new();

my $thrd = threads->create(\&image_loader);

my $mw = MainWindow->new;

# ...the usual widget building here...

my $repeat_id = $mw->repeat($interval, \&image_handler);

$cmdq->enqueue('GO');

MainLoop;


sub image_handler { 
    return unless $respq->pending;
    
    my $buffer = $respq->dequeue();
    ...load into your frame here...
    $cmdq->enqueue('GO');
}
#
#    assumes your image loader persists
#
sub image_loader {
    while (1) {
        my $go = $cmdq->dequeue();
        last 
            if ($go eq 'STOP');
        ...do your image loading business here...
        $respq->enqueue($imagebuffers);
    }
}

[download]
Perl Contrarian & SQL fanboy

In reply to Re: How to not wait for a thread by renodino
in thread How to not wait for a thread by Sixtease

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.