First, Tk::repeat is a quick shortcut for Tk::after, read "perldoc Tk::after". Look thru Tk::after's methods to see if there is something you can use. Second, you didn't show a complete code example, but with Tk timers, if you declare them BEFORE you create them, you can use their variable name within the callback, like:

#pseudocode

my $timer;
# code update line below, I forgot to define $timer
$timer = $mw->repeat( 50, {    #you can use $timer here   
                                 if $whatever, $timer->cancel;
                              }  );    
# declare outside the callback, otherwise a $timer cannot cancel itsel
+f
[download]

If you really want to get into a select style usage, within Tk, it dosn't work well, because it will interfere with the eventloop. But there is a workaround. See Tk::Trace in Simple Tk Gauge

Thank you zentara, about cancel/destroy the repeat object, I do that from the caller routine for a better "logistic" administration (yes, the missing code would show that). I know practically nothing about select function but after some tests I suspected the problems comes from it, so you reinforsed my suspects, I bookmarked your post "Simple Tk Gauge" and I'll study it later. After a first look to the after method, it seems there is nothing usable to solve that problem, I think I'll use the Tk::waitVariable method ( $widget->waitVariable(\$var); ) it should work. I'll post more on this thread if I'll discover more solutions. Thank you again!

...a doubt rised about the "waitVariable" method is that I suspect that if the timer of repeat is too small, the repeat could set the variable before the creation of waitVariable object and the program could block:

sub xyz{
  $wid->repeat(1, sub{ $var=1; } ); # after 1 millisecond $var==1
  # 1 ms... 2ms... 3ms...
}

{
  &xyz;
  # 6 ms... 7ms... 8ms...
  $widget->waitVariable(\$var); # will this wait indefinitely because 
+the var was already changed???
  # Continue... never will happen
}
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It depends on how repeat works (I don't know); but because it returns before the first pause (see Tk::after documentation) should be possible to do a sufficient reliable use of waitVariables, even if this appears to me like a bad patch...

Sorry it didn't work for you, but I noticed I didn't quite show the code correctly, neglecting to define $timer, after declaring it as a global. That's maybe why your script dosn't cancel. Also, there is a method DoOneEvent which is very useful to force Tk to update everything before proceeding.

Here is a little something for you to play with, for waitVariable

#!/usr/bin/perl
use warnings;
use strict;
use Tk;

$|=1;

my $count = 0;
my $loop  = 0;
my $mw    = new MainWindow();

$mw->Label( -textvariable => \$count )->pack;

$mw->Button( -text => 'Start', -command => \&long_job )
  ->pack( -side => 'left' );

$mw->Button( -text => 'Stop', -command => sub { $loop = 0; print "$cou
+nt\n"; } )
  ->pack( -side => 'left' );

MainLoop();




sub long_job {

my $var;
my $timer = $mw->repeat(100, sub{$var++} ); 

   $loop =1;       
   while($loop){
          $loop++;
          $mw->waitVariable(\$var);
          $count++;
         }
  DoOneEvent();  #must call or will block gui
}
[download]

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I'm not really a human, but I play one on earth.
Old Perl Programmer Haiku ................... flash japh