On Mon, Jul 07, 2008 at 10:58:36PM -0400, James Scott Jr wrote: > G, > > The basic design decision to use fork() as a way to do work in the > background flawed. fork()ing is not practical for gtk program. While > fork() has been a valid option for many non-gui programs in the absence > of threads, either g_thread_create() or pthread_create(). Today it is > not very useful -- as in stop doing it now! > > Consider instead using a valid multi-threaded implementation like > g_threads_xxx() for GTK based programs. Or if full multi-threading is > not required, look at g_timeout_add() which is a background timer > routine that can serve as one or more background execution units; neatly > inside an gtk context.
This is not a very practical solution if I want to quit the gtk program and go home... The example I gave was just an example. I want to create a process that run for a VERY long time. (a week). And to have the GUI running allong is not a solution. This process don't need to communicate with the GUI. And if so I can connect to the process with a socket and ask for services. > > $ devhelp > $ gtk-demo > > The above two program you be pre-installed on your Linux machine: > devhelp has the gtk and glib api documentation, and gtk-demo shows you > many of the gtk/glib features in action. > > Having said the multi-thread phrase, here is another word of caution. > In GTK only the main or ONE thread can safely interface with GTK api > calls that change the display. Using more than one thread to call gtk > apis at the same time will fail or cause a sigfault. The context of GTK > being your front-end to X11 is the source of this > none-thread-safe-caution; it is in how gtk MUST interact with X that > placing the multi-thread restriction. There are elegant work-arounds > this issue. > > Here is a link to the classic FAQ answer on Multi-threaded GTK programs: > http://library.gnome.org/devel/gtk-faq/stable/x482.html > > Regards, > James, Tanks for your answer but I don't thing threads is the solution in my case. > > On Mon, 2008-07-07 at 23:03 +0200, G Hasse wrote: > > Hello, > > > > I have a small demo app. This works on FreeBSD but I can't > > get to work on Linux. I know that in Linux setsid will fail > > if the child has the same session_id as the parent. So on > > Linux you must fork twice. But it also seems that the parent > > must do an exit. And I don't want that. The code is not very > > long - so I include it here. > > > > ---<snipp>--- > > //---------------------------------------------------------------------- > > // > > // $Id: GtkFork.c,v 1.2 2008/07/07 20:29:17 gorhas Exp $ > > // > > // Experiment to run a thing in background > > // This works on FreeBSD but not on Linux... > > // > > // Build with > > // > > // CFLAGS := `pkg-config glib-2.0 --cflags` `pkg-config gtk+-2.0 > > --cflags` > > // LDFLAGS := `pkg-config glib-2.0 --libs` `pkg-config gtk+-2.0 --libs` > > // > > // cc $(CFLAGS) -o GtkFork GtkFork.c $(LDFLAGS) > > // > > //---------------------------------------------------------------------- > > > > #include <gtk/gtk.h> > > #include <stdlib.h> > > #include <stdio.h> > > #include <time.h> > > #include <string.h> > > > > //---------------------------------------------------------------------- > > // run_btn_callback > > // > > // Try to run something in the background > > // > > //---------------------------------------------------------------------- > > static void run_btn_callback (GtkWidget *button, gpointer data) > > { > > > > int loops_to_run = 0; > > int i = 0; > > int pid = -1; > > int ret = -1; > > > > // Skriv ut innehÃ¥llet pÃ¥ skärmen > > printf("Clicked..\n"); > > printf("Data was: %s\n", gtk_entry_get_text( data )); > > > > loops_to_run = atoi( gtk_entry_get_text(data)); > > > > // We dont want to wait very long... > > if( loops_to_run > 60 ) > > { > > loops_to_run = 60; > > printf("Adjusting to 60 loops...\n"); > > } > > printf("Loops to run: %d\n", loops_to_run ); > > > > > > > > printf("We make a daemon\n"); > > if ( ( pid = fork() ) < 0 ) > > { > > // Something went wrong > > printf("We could not fork.... just exit"); > > exit(-1); > > } > > else if ( pid != 0 ) > > { > > > > // This is the parent process > > printf("The background process have pid: %d\n", pid); > > return; > > } > > > > // Quit gtk > > gtk_main_quit(); > > > > // Become session leader > > ret = setsid(); > > if( ret == -1 ) > > { > > perror("We could not be session leader\n"); > > exit(-1); > > } > > > > // Set umask for safety > > umask(0); > > > > // Set root dir > > chdir("/"); > > > > > > for( i = 0; i < loops_to_run; i++ ) > > { > > printf("We are running: %d\n", i ); > > sleep(1); > > } > > > > exit(0); > > > > } > > > > //---------------------------------------------------------------------- > > // When we quit > > //---------------------------------------------------------------------- > > static void quit_callback() > > { > > gtk_main_quit (); > > } > > > > > > //---------------------------------------------------------------------- > > // main > > // > > // Creates a gtk windows to specify how many loops > > // the daemon should run. > > // > > //---------------------------------------------------------------------- > > int > > main (int argc, char **argv) > > { > > > > GtkWidget *mainwin = 0L; > > GtkWidget *number_entry = 0L; > > GtkWidget *run_btn = 0L; > > GtkWidget *vbox = 0L; > > > > /* Initialize i18n support */ > > printf("Locale is: %s\n", gtk_set_locale () ); > > > > /* Initialize the widget set */ > > gtk_init (&argc, &argv); > > > > /* Create the main window */ > > mainwin = gtk_window_new (GTK_WINDOW_TOPLEVEL); > > > > /* Set up our GUI elements */ > > vbox = gtk_vbox_new (FALSE, 0); > > > > number_entry = gtk_entry_new(); > > > > run_btn = gtk_button_new_with_label("Just run"); > > > > gtk_container_add (GTK_CONTAINER (mainwin), vbox); > > gtk_box_pack_start (GTK_BOX (vbox), number_entry, TRUE, TRUE, 0); > > gtk_box_pack_start (GTK_BOX (vbox), run_btn, TRUE, TRUE, 0); > > > > > > // Function to call when main window is destroyed > > g_signal_connect (G_OBJECT (mainwin), > > "destroy", > > GTK_SIGNAL_FUNC (quit_callback), > > NULL); > > > > // Function to call when we click the button > > g_signal_connect(GTK_OBJECT(run_btn), "clicked", > > G_CALLBACK(run_btn_callback), > > number_entry); > > > > /* Show the application window */ > > gtk_widget_show_all (mainwin); > > > > /* Enter the main event loop, and wait for user interaction */ > > gtk_main (); > > > > /* The user lost interest */ > > return 0; > > > > } > > > > //------------------------------------------------------------------ > > // END > > //------------------------------------------------------------------ > > > > ---<snipp>--- > > > -- Göran Hasse ---------------------------------------------------------------- Göran Hasse email: [EMAIL PROTECTED] Tel: 019-450105 Raditex AB http://www.raditex.se Planiavägen 15, 1tr Mob: 070-5530148 131 34 NACKA, SWEDEN OrgNr: 556240-0589 VAT: SE556240058901 ------------------------------------------------------------------ _______________________________________________ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
