#!/usr/bin/perl
use Tk;
my $mw = tkinit;

$mw->withdraw;  # hide the empty mainwindow

my $filename = $mw->getOpenFile();
# or
# my $filename1 = $mw->getSaveFile();

#if you want a filename for reading or writing respectively.
print "$filename\n";

use Tk::Event qw(DONT_WAIT);
#MainLoop;

##</code><code>##

#!/usr/bin/perl
# untested
my $old = *{Tk::MainLoop}{CODE};

  *Tk::MainLoop = sub { ... };

#Or use DoOneEvent() instead of MainLoop(), 
#to run only one event loop at a time. 
#An even better idea would be to look at 
#the test suite for Tk, and see how they handled it...

##</code><code>##

#!/usr/bin/perl

# by joost of perlmonks  , original node number lost

use Tk::Event qw(DONT_WAIT);

while (1) {
if ($self->run) {          # test if we need to process
$self->process_a_bit()  # process a tiny bit
}
return if $self->quit;     # test if quit status was set
DoOneEvent(DONT_WAIT);     # do normal Tk event
select undef,undef,undef,0.0001; # wait for a bit
}

# I did this, because my processing was not easily adjusted 
# into the normal Tk::Eventloop processing and it needed to 
# be called a lot ("live" 44Kz audio stream processing, 
# with 100 samples per process_a_bit call)

# If you want to go this route, you want to adjust the timing 
# of the select() and process_a_bit() calls until your GUI 
# and processing run fast enough, and it doesn't lock up 
# the whole machine when there is no processing being done :-)

# Alternatively, if you're able to run your processing based 
# on file events or signals, you can take a look at the 
# Tk::Eventloop documentation for registering extra events 
# in the normal MainLoop.