Re: subprocess delay on Windows with Perl/Tk

Here is a version that runs just fine on Windows XP ... using threads.

use strict;
use Tk;
use File::Spec;
use threads;
use Thread::Queue;

my $RequestQ  = Thread::Queue->new;
my $worker    = threads->new(\&worker);

my $top = MainWindow->new();

my $menubar = $top->Menu(-type => 'menubar');
$top->configure(-menu => $menubar);

my $filemenu = $menubar->cascade(-label => '~File', -tearoff => 0);
$filemenu->command(-label => '~Report extract',
                   -command => [\&report_extract],
                   );

$filemenu->command(-label => 'E~xit',
                   -command => [\&Shutdown],
                   );
print STDERR "there's a tiny window open, it's small but it's there\n"
+;



MainLoop();
 print STDERR "Exit Main loop \n";

############################
sub Shutdown{
    $RequestQ->enqueue(undef); # quit the worker
    $worker->join;
    print STDERR "FINISHED Shutdown\n";
    exit; # Clean up Tk
}

############################

sub report_extract {
   my $tmpdir = File::Spec->tmpdir();


   open (F, ">$tmpdir\\xx.csv") || die $!;
   print F "aaa,bbb,ccc\nddd,eee,fff\n";
   close F;
   my $cmd = "start $tmpdir\\xx.csv";
   print STDERR "running $cmd\n";
   $RequestQ->enqueue($cmd);

}
##################
sub worker{
    while (my $target = $RequestQ->dequeue){
      print STDERR "Request $target Read\n";
      system $target;
      print STDERR "Finished target\n";

    }
    print STDERR "Thread exit\n";
}
[download]

Offense, like beauty, is in the eye of the beholder, and a fantasy.
By guaranteeing freedom of expression, the First Amendment also guarantees offense.

Comment on Re: subprocess delay on Windows with Perl/Tk Download Code

Replies are listed 'Best First'.
Re^2: subprocess delay on Windows with Perl/Tk by kgoess (Beadle) on Jun 05, 2004 at 15:03 UTC
Oooh! Now that's fancy. I like it. What was the train of thought that led you to consider threads as a solution? It never would have occurred to me.	[reply]
Re^3: subprocess delay on Windows with Perl/Tk by NetWallah (Canon) on Jun 05, 2004 at 17:08 UTC
I had always found "fork" non-intutive, and a pain (on Win32), because you needed a mechanism to exchange data between parent and child - the working ones are complicated (to my simple mind). I had tested perl threads on Win32 and found that to be robust, intutive and, to my twisted brain, very logical. The thread queue model rules!! I had never tried using threads with Tk - so I enjoyed playing with your code. Cheers. Offense, like beauty, is in the eye of the beholder, and a fantasy. By guaranteeing freedom of expression, the First Amendment also guarantees offense.	[reply]
Re^4: subprocess delay on Windows with Perl/Tk by BrowserUk (Patriarch) on Jun 05, 2004 at 18:19 UTC
The nice, if slightly strange thing is that as fork is emulated using threads (win32), you can actually use Thread::Queue to communicate between forked pseudo-processes. #! perl -slw use strict; use threads; use Thread::Queue; $\|=1; my $QpRead = new Thread::Queue; my $QkRead = new Thread::Queue; if( defined( my $kid=fork() ) ) { print 'Forked'; if( $kid ) { # Parent print 'Pop ', $$; while( 1 ) { print "Kid said: ", $QpRead->dequeue while $QpRead->pendin +g; Win32::Sleep rand 1000; $QkRead->enqueue( 'Blah ' x rand 10 ) if rand > .5; } } else { # Kid print 'Kid ', $$; while( 1 ) { print "Pop said: ", $QkRead->dequeue while $QkRead->pendin +g; Win32::Sleep rand 1000; $QpRead->enqueue( 'Blah ' x rand 10 ) if rand > .5; } } } else { die "Fork failed: $!"; } __END__ P:\test>357845 Forked Pop 416 Forked Kid -1140 Pop said: Blah Blah Blah Kid said: Blah Blah Blah Blah Kid said: Blah Kid said: Blah Blah Blah Blah Kid said: Blah Blah Blah Blah Blah Blah Blah Blah Kid said: Blah Blah Blah Blah Blah Pop said: Blah Blah Kid said: Blah Blah Blah Blah Blah Blah Blah Pop said: Blah Blah Blah Blah Blah Blah Pop said: Blah Blah Blah Blah Blah Blah Blah Pop said: Kid said: Blah Blah Blah Blah Pop said: Blah Blah Kid said: Blah Blah Blah Blah Blah Blah Blah Blah Kid said: Blah Blah Blah Blah Blah Blah Blah Blah Pop said: Blah Blah Blah Blah Blah Blah Pop said: Blah Blah Blah Blah Blah Blah Blah Blah Kid said: Blah Blah Blah Blah Blah Blah Blah Pop said: Blah Blah Blah Blah Blah Kid said: Blah Blah Blah Blah Blah Kid said: Blah Pop said: Blah Blah Blah Blah Blah Blah Blah Blah Kid said: Blah Blah Blah Blah Blah Blah Blah Pop said: Blah Kid said: Blah Blah Blah Blah Blah Pop said: Blah Blah Blah Kid said: Blah Terminating on signal SIGINT(2) [download] Examine what is said, not who speaks. "Efficiency is intelligent laziness." -David Dunham "Think for yourself!" - Abigail	[reply] [d/l]