From: Bauduin Raphael <rb@...>
Date: 2004-12-18T22:32:10+09:00
Subject: Re: rubyqt,   popen  problem in a log viewer

Hi,

Thanks for the tip about QProcess, I'll experiment with it later.
For the time being, I've implemented nobu nokada's suggestion.

I still have the problem refreshing the widget though....

With this code:

         Thread.new("/tmp/test") do |f|
             begin
                 tail = IO.popen("/usr/bin/tail -f #{f}","r")
                 while line = tail.gets
                     hello.append line.chomp
                     puts line.chomp
                 end

             ensure
                 puts "killing #{tail.pid}"
                 Process.kill("INT", tail.pid)
                 tail.close
             end
         end

the while loops (updating the widget AND printing line in the terminal) 
seems to be run only when activity occurs in the window (click, entering 
window).

How comes the line is printed in the terminal only when activity occurs 
in the window?

Thanks for your help

Raph



Richard Dale wrote:
> Richard Dale wrote:
> 
>>You could start 'tail' with a Qt::Process instead of popen(), as it ties
>>in with Qt signals/slots 
> 
> 
>>and shuts down the sub process on application 
>>exit
> 
> Actually I'm wrong - Qt doesn't do this, you need to connect to the
> 'aboutToQuit()' application signal, and kill the 'tail' process on exit:
> 
>         @proc = Qt::Process.new(self) {
>             addArgument "/usr/bin/tail"
>             addArgument "-f"
>             addArgument "/tmp/test"
>         } 
>                 
>         connect( @proc, SIGNAL('readyReadStdout()'),
>                  self, SLOT('readFromStdout()') )
> 
>         connect( $kapp, SIGNAL('aboutToQuit()'),
>                   self, SLOT('shutdown()') )   
>         @proc.start
>     end
>         
>     slots 'readFromStdout()', 'shutdown()'
>         
>     def readFromStdout
>         lines = @proc.readStdout
>         @hello.append lines.to_s
>     end
>         
>     def shutdown
>         @proc.kill
>     end
> 
> -- Richard