Recalculation of timeouts with g_timeout_add

[Mitko Haralanov <mitko qlogic com>]

I have a question about g_timeout_add's timeout recalculation.

Currently, the next call time is calculated based on <time of callback
thread start> + <timeout given to g_timeout_add>. This means that if I
call g_timeout_add with a timeout of 20*1000 msecs (20 seconds) and my
callback takes 10 seconds to complete, my callback will be called 10
seconds after it completes. Here is an example:

#include <gtk/gtk.h>
#include <glib.h>
#include <time.h>
#include <stdio.h>

gboolean callback (gpointer data) {
     int timeout = *((int *)data);
     printf ("callback called at: %lu\n", time (NULL));
     sleep (timeout);
     printf ("callback returns at: %lu\n", time (NULL));
     return TRUE;
}

int main (int argc, char **argv) {
     int timeout = 10;
     gtk_init (&argc, &argv);
     g_timeout_add (20*1000, callback, (gpointer)&timeout);
     gtk_main ();
}


will produce this:
callback called at: 1210893003
callback returns at: 1210893013
callback called at: 1210893023
callback returns at: 1210893033
callback called at: 1210893043

What I would to happen is that my callback is called 20 seconds after
it returns, not 20 seconds after it is started.

How can I accomplish this?

-- 
Mitko Haralanov
==========================================
What this country needs is a good five cent microcomputer.