Re: gtk_timeout_add / SIGALRM with gtk

[Colin Thomas <colin in2fab com>]

Hi Todd,

Apologises for the delay in getting back, but I have been profiling some
code and trying to speed up a routine that is called 1.3 billion times.

What I have done is take you ideas and create a thread to periodically
refresh the main window, which is started and stopped on the enter and
exit of the button being depressed.


i.e.

1. Call back for button being depressed:
========================================
void
on_button_clicked                     (GtkButton       *button,
                                        gpointer         user_data)
{
 ////////////////////////////////////////
 g_mutex_lock(lock);
 //Set global flag to mark thread running
 working = true;
 g_mutex_unlock( lock);

 //Start the thread
 tid = g_thread_create((GThreadFunc) RunThread, NULL , FALSE , NULL);
 ////////////////////////////////////////

 //Large loop to burn cpu time
 unsigned int count = 0;
 for (
      count = 0;
       count < 100000000;
       count++
       )
 {
 }

 ////////////////////////////////////////
 //job finished, inform thread to kill itself
 g_mutex_lock(lock);
 working = false;
 g_mutex_unlock( lock);

 //Sleep for the same amount of time as the thread refresh time, to 
 //ensure that the thread sees working as false and dies, before a
 //possible 2nd thread is created, and two threads end up running in
 //parallel.
 g_usleep(500000);      
 ////////////////////////////////////////
}

2. Function to refresh the main window:
=======================================
void RunThread ()
{
 //Thread will die when work set to false (when main job completes)
 while(working)
 {
  gtk_widget_draw (pTOPWindow,NULL);             
  gdk_flush();
  //put thread to sleep for 1/2 sec => refresh every 1/2 sec
  g_usleep(500000);     
 }
}

3. Enabling code in main routine:
=================================

int
main (int argc, char *argv[])
{

 g_thread_init(NULL);
 gdk_threads_init();
 gtk_init(&argc, &argv );       
 lock = g_mutex_new();  
.
.
.

This seems to be okay.. can you see any possible flaws?

Many thanks again for your help.

Best regards

Colin Thomas