Re: 2 questions regarding a perl daemon with a GTK interface

[Etienne Grossmann <etienne anonimo isr ist utl pt>]

  Hi Greg,

  in fact, after answering your mail, I realized that I had never used
successfully the 'input_add' way of communicating between processes.

What I did succeed in doing is spawning a child and pass data to it
through a temporary file; the child is told to read the temp file when
it receives a USR1 or USR2 signal (set the corresponding signal
handler). I guess data could be sent back in the same way, through
another temp file.

  Cheers,

  Etienne

From: gfricke hushmail com
#  Thank you to all those who responded to my initial post.  I have since successfully 
#  implemented the "delete_event" signal to spawn my exit dialog window, so 
#  problem 2 is solved :)  However, I'm note sure the solutions given for my 
#  first problem work in my case (I could be wrong, it may be exactly what 
#  I need but I have goten it to work yet).  What I need is the ability to 
#  start and stop the daemon dependant on what buttons are clicked.  I have 
#  tried to implement this by way of a variable "$daemonStarted" equal to 1 
#  for true and 0 for false.  I used the fork command and wrote a condition 
#  that basically says, if $daemonStarted then listen for request else do nothing. 
#   Unfortunately, I discovered that when I click the start daemon button, 
#  the gui child process changes the value of its copy of $daemonStarted but 
#  the parent process' variable remained unchanged.  I guess what I really 
#  need is a way to have the child process and the parent process access/modify 
#  the same variables, or for Gtk to somehow sit in the background, avoid the 
#  use of fork and allow a daemon loop to execute at the same time.  Any suggestions/links/examp
#  les 
#  would be greatly appreciated.  Thanks in advance.

#  Greg  

#  At Thu, 10 May 2001 09:02:07 +0100, Etienne Grossmann <etienne anonimo isr ist utl pt> 
#  wrote:

#  >
#  >
#  >  Hi,
#  >
#  >From: gfricke hushmail com
#  >#  All,
#  >#  I recently used glade to build my first perl program with a GUI
#  >#  interface.  I have come across two problems that I haven't been
#  >#  able to figure out.  My GTK experience is very minimal and my perl
#  >#  expertise is limited to just a few programs.
#  >
#  >#  Problem 1 - How do I send GTK to the background so that I can run 
#  >a
#  >#  daemon loop listening for remote connections, yet having the GTK
#  >#  portion of the program still sending all the actions/signals to
#  >#  thier appropriate functions/handlers?  If i enter my daemon loop
#  >#  after the Gtk->mainl command the loop never executes.  Likewise if
#  >#  I insert the daemon loop before the Gtk->main call the window never
#  >#  appears.
#  >
#  >  Maybe that's what you are looking for, taken from the perl-gtk
#  >tutorial (http://personal.riverusers.com/~swilhelm/gtkperl-tutorial):
#  >======================================================================
#  >Monitoring IO
#  >
#  >A nifty feature of GDK (the library that underlies GTK), is the
#  >ability to have it check for data on a file descriptor for you (as
#  >returned by open() or socket()). This is especially useful for
#  >networking applications. The function:
#  >
#  >$id = Gtk::Gdk->input_add( $source, $condition, \&function, @data );
#  >
#  >takes a file descripter you want watched as the first argument, and
#  >the second argument specifies what you want GDK to look for. This may
#  >be one of:
#  >
#  >'read' - Call your function when there is data ready for reading on
#  >         your file descriptor.
#  >
#  >'write' - Call your function when the file descriptor is ready for
#  >         writing
#  >======================================================================
#  >