From: Bauduin Raphael <rb@...>
Date: 2004-12-17T06:42:13+09:00
Subject: rubyqt,   popen  problem in a log viewer

Hi,

I'm looking at Qtruby, trying to write a little log view app.
I'm basing the app on the p3 app from the tutorial found here:
http://developer.kde.org/language-bindings/ruby/kde3tutorial/p3.html

I modify it like that:

         hello = Qt::TextEdit.new( "", "", self)
         hello.textFormat = Qt::LogText

         setCentralWidget hello

         Thread.new("/tmp/test") do |f|
             tail = IO.popen("/usr/bin/tail -f #{f}","r")

             while line = tail.gets
                 hello.append line.chomp
		#hello.refresh
             end
         end


First problem: when I qui the app, the tail -f continues to run.
I also tried to put the while in a block passed to IO.popen, with the 
same result. This then understandably results in the message

/usr/bin/tail: write error: Broken pipe
/usr/bin/tail: write error

in the terminal from which I started the app when a new line is appended 
to the watched file.

I have also problems refreshing the widget when a new log line is 
appended. If I uncomment hello.refresh after hello.append, only the 
first line is displayed in the widget when I start the app, and when new 
log lines are appended to the watched file, I get the broken pipe in the 
terminal. When replacing hello.refresh by puts line.chomp, the program 
works fine, except for the refrech problem.....

Thanks for your help.

Raph