Your example is confusing. Are you trying to write the system call to the OUTFILE filehandle? Make a better example please, and explain exactly what you want to occur.

So it's hard to say from your limited code example, but you are probably running into a situation where system is blocking the Tk event loop. Tk (and all GUI's) run a thing called the event loop..... your new MainWindow; and MainLoop; statements are what start it. Once MainLoop gets called, a big loop starts running behind the scenes, doing everything you ask, on a schedule. When you put a while(1) loop in Tk, or a system call, it will hog the whole loop until it finishes (system returns).

So...... you want to avoid system calls, unless they are in a piped open or somehow forked off. Since you are writing the results to an output file ( not collecting the results internally), you can fork off the system call, and let Tk keep running it's loop. So instead of system, fork and exec. Like: 

 if(fork() == 0){ 
       exec( "$executable $title" )
         }

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I don't use windows, so there may be some special syntax you need to exec your command. See how to create independent process? and Perl Tk: opening a file in its original format for more ideas.
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In reply to Re: Tk - system() by zentara
in thread Tk - system() by lil_v

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