There is IPC::Run, but my approach to this has always been to do a (blocking) read from the pipe in a separate thread and stuff the lines into a Thread::Queue, from where the front end code (or whatever else) reads.

Multi threading could be an answer, but Tk is not thread safe.

Tk isn't "thread-safe", but it does run perfectly safely in a single thread.

That is, you can have as many background threads running as you need in your TK app, provided that none of those other threads attempt to talk directly to the GUI.

The basic method is that you start all your background threads runnung before you require Tk and build your GUI. And you then use Thread::Queue(s) to send commands from the GUI to the worker threads and another to receive back results. It is a simple, efficient mechanism that avoids all the fuss and bother of buffered pipes or sockets and select loops.

@BrowserUk,

thanks for your contribution. Your approach seems to be the most straightforward. It is simple and powerful. With this approach (at least on my platform) you don't even need require. You can go ahead and use Tk.

Believe it or not, the following code works:


use Tk;

use threads;
use Thread::Queue;

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

my $thr = threads->create(sub
{

######################################################
# thread working on input received from Tk MainWindow

do
{

my $item = $q->dequeue();

print "Received: $item\n";

}
while(1);

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

})->detach();

######################################################
# here comes the Tk stuff

$mw=new MainWindow;

$mw->repeat(1000,\&handler);

MainLoop;

sub handler
{
$i++;
$q->enqueue("command $i");
}

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