From: Shea Martin <null@...0>
Date: 2005-10-13T21:01:54+09:00
Subject: threading in win32

I have a TK app.  On a button presses, I call a windows copy command 
which can take up to 10 minutes to run. In order to not freeze the GUI, 
so that the gui can be doing other stuff, I launch the command in a thread.

Running the command with system, does not let me get the output of the 
command, thought it does not lock gui up at all.  So, I tried two other 
versions.  I had the most success with version 3. I believe version 3 is 
what the TkTextIo example uses in ruby 1.8.3. See below.

# callback for tk button press
def buttonPress
   Thread.new do
     Button.state( "disable" );
     runCommand( "copy /Y bigfile1 dest1" );
     runCommand( "copy /Y bigfile2 dest2" );
     runCommand( "copy /Y bigfile3 dest3" );
     Button.state( "active" );
   end
end

#version 1
def runCommand( cmd )
   system( cmd )
end

#version 2
def runCommand( cmd )
   IO.popen( cmd ) do | cmd_out |
     cmd_out.each_line do | line |
       MyTextArea.insert( 'end', line, 'normal' )
     end
   end
end

#version 3
def runCommand( cmd )
   cmd_pipe = IO.popen( cmd )
   t = Thread.new { cmd_pipe.each{ | line | addText( line ) } }
   t.join
end

Only version 1 allows teh gui to remain responsive.  Unfortunately it 
does not capture the output of the copy command.  I would like to 
something with a fork, though win32 ruby does not seem to support it.

Any ideas.

Thanks,

~S