Why does using `g_application_run` create a lag of ~25 seconds?

Question

I'm trying to learn GTK3, but the documentation is problematic at best. The most frustrating problem comes from using g_application_run. It seems to create a lag of ~25 seconds when the program is run.

Here is the example:

#include <gtk/gtk.h>

static void activate(GtkApplication *app, gpointer user_data)
{
    GtkWidget *window;

    window = gtk_application_window_new(app);
    gtk_window_set_default_size(GTK_WINDOW(window), 300, 200);
    gtk_widget_show_all(window);

exit(0);
}

int main(int argc, char **argv)
{
    GtkApplication *app;

    app = gtk_application_new("org.gtk.example", G_APPLICATION_FLAGS_NONE);
    g_signal_connect(app, "activate", G_CALLBACK(activate), NULL);
    g_application_run(G_APPLICATION(app), argc, argv);
    g_object_unref(app);

    return 0;
}

Very minimal, it creates a window, shows it and exits. Basically testing the time to load. When run with time I get the following results:

$ time ./capplication_new 

real    0m25.177s
user    0m0.151s
sys     0m0.014s

Over 25 seconds for the program to run. This is really unacceptable. What is most frustrating about this is that it's the newest code you're supposed to start using. But if I run this minimal example of creating a window, showing it and exiting:

#include <gtk/gtk.h>

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

    GtkWidget *window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    gtk_window_set_default_size(GTK_WINDOW(window), 300, 200);
    g_signal_connect(window, "destroy", G_CALLBACK(gtk_main_quit), NULL);
    gtk_widget_show(window);

exit(0);

    gtk_main();
}

When run with time, the results are:

$ time ./binit 

real    0m0.139s
user    0m0.108s
sys     0m0.023s

Is there a way to stop it from lagging? Why is it lagging? Why is this the new code if it lags?

**EDIT:

$ uname -a
Linux testing 5.10.0-11-amd64 #1 SMP Debian 5.10.92-1 (2022-01-18) x86_64 GNU/Linux

Answer 1

I didn't find out why it was happening, but I was able to find a solution.

You need to add the following to your .xinitrc or .xsession file:

dbus-update-activation-environment --systemd DBUS_SESSION_BUS_ADDRESS DISPLAY XAUTHORITY