Re: Problem running the GTK main loop in a separate thread (different from the main one).

[Cristi Cobzarenco <cristi cobzarenco gmail com>]

Hi,

Yeah, this works for me to, this is equivalent to my "create_in_gt" flag being on. Problem is if you try creating the widgets in the main thread.

Does this work for you?

#include <gtk/gtk.h>

static gpointer _gtkthread(gpointer a_data)

{

       gdk_threads_enter();

       gtk_main();

       gdk_threads_leave();

                                               

       return NULL;

}

int main(int a_argc,char **a_argv)

{

       GThread *l_th;

       GtkWidget *l_win;

       GtkWidget *l_but;

       g_thread_init(NULL);

       gdk_threads_init();

       gtk_init(&a_argc,&a_argv);

       l_th = g_thread_create(_gtkthread,NULL,TRUE,NULL);

       g_usleep(2000000); // wait two seconds to be sure that the main loop started

                       

       gdk_threads_enter();

       l_win = gtk_window_new(GTK_WINDOW_TOPLEVEL);

       l_but = gtk_button_new_with_label("My Button");

       gtk_container_add(GTK_CONTAINER(l_win),l_but);

       gtk_widget_show_all(l_win);

       gdk_threads_leave();

       g_thread_join(l_th);

       return 0;

}

On Sat, Aug 29, 2009 at 3:45 PM, Jorge Opaso Pazos <jorge opaso gmail com> wrote:

Hello,

This works for me:

#include <gtk/gtk.h>

static gpointer _gtkthread(gpointer a_data)
{
       GtkWidget *l_win;
       GtkWidget *l_but;
                       
       gdk_threads_enter();
       l_win = gtk_window_new(GTK_WINDOW_TOPLEVEL);
       l_but = gtk_button_new_with_label("My Button");
       gtk_container_add(GTK_CONTAINER(l_win),l_but);
       gtk_widget_show_all(l_win);

       gtk_main();
       gdk_threads_leave();
                                               

       return NULL;
}

int main(int a_argc,char **a_argv)
{
       GThread *l_th;

       g_thread_init(NULL);
       gdk_threads_init();
       gtk_init(&a_argc,&a_argv);
       l_th = g_thread_create(_gtkthread,NULL,TRUE,NULL);
       g_thread_join(l_th);

       return 0;
}


Atentamente,

Jorge Opaso Pazos
AUTOLogic LTDA




El 29-08-2009, a las 7:35, Cristi Cobzarenco escribió:

Hi, I've been using GTK for a pretty long time but I've never used threads with it and I'm not able to properly run the GTK main loop in a separate thread.
More to the point if I create a window, for example, in a thread other than the GTK one, it becomes unresponsive. Other GTK calls (that don't create widgets) seem to work fine, however.
I've attached a sample program to show what I mean, the flag "create_in_gt" sets whether to create the widgets in the GTK thread or in the main one.

Is this normal behaviour, am I not supposed to do this, or is it a bug?

(NOTE: The first time I've sent this message it was detected as spam so I'll include the file instead of attaching it)

threadtest1.cpp:
#include <gtk/gtk.h>

const int create_in_gt = FALSE; // Whether to create the widgets in the GTK thread.
GtkWidget *win, *but;

// Creates a window with a button in it.
// This function will be called in the GTK thread if "create_in_gt" is TRUE
// or in the main thread otherwise.
int create_widgets(void*) {
   win = gtk_window_new(GTK_WINDOW_TOPLEVEL);
   but = gtk_button_new_with_label("My Button");

   gtk_container_add(GTK_CONTAINER(win),but);
   gtk_widget_show_all(win);
   return FALSE;
}

// The GTK thread function
void* gtkthread(void *) {
   gdk_threads_enter(); // GTK calls to follow - locking.

   // Inits gtk in this thread (I have tried initing it in both threads, the
   // result is the same.)
   gtk_init(NULL,NULL);

   // Creates the widgets if neccesary and then enters the main loop.
   if( create_in_gt ) create_widgets(NULL);
   gtk_main();

   gdk_threads_leave(); // GTK calls end here - unlocking
}

int main(int argc, char *argv[]) {
   g_thread_init(NULL); // Init threads in main thread.
   gdk_threads_init();

   // Creates the GTK thread.
   GThread *gt = g_thread_create(gtkthread, NULL, TRUE,NULL);

   // Waits 1 second, creates widgets if neccesary then, waits 2 more seconds.
   g_usleep( 1000000 );
   if( !create_in_gt )
       g_idle_add(create_widgets,NULL);
   g_usleep( 2000000 );

   gdk_threads_enter(); // Quits GTK safely.
   gtk_main_quit();
   gdk_threads_leave();

   g_thread_join(gt); // Waits for GTK to quit.

   return 0;
}

--
Cristi Cobzarenco

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Cristi Cobzarenco