#include <gtk/gtk.h>

static gboolean

fill (gpointer   user_data)

{

  GtkWidget *progress_bar = user_data;

  /*Get the current progress*/

  gdouble fraction;

  fraction = gtk_progress_bar_get_fraction (GTK_PROGRESS_BAR (progress_bar));

  /*Increase the bar by 10% each time this function is called*/

  fraction += 0.1;

  /*Fill in the bar with the new fraction*/

  gtk_progress_bar_set_fraction (GTK_PROGRESS_BAR (progress_bar), fraction);

  /*Ensures that the fraction stays below 1.0*/

  if (fraction < 1.0) 

    return TRUE;

  return FALSE;

}

static void

activate (GtkApplication *app,

          gpointer        user_data)

{

  GtkWidget *window;

  GtkWidget *progress_bar;

  gdouble fraction = 0.0;

  /*Create a window with a title, and a default size*/

  window = gtk_application_window_new (app);

  gtk_window_set_title (GTK_WINDOW (window), "ProgressBar Example");

  gtk_window_set_default_size (GTK_WINDOW (window), 220, 20);

  /*Create a progressbar and add it to the window*/

  progress_bar = gtk_progress_bar_new ();

  gtk_container_add (GTK_CONTAINER (window), progress_bar);

  /*Fill in the given fraction of the bar. Has to be between 0.0-1.0 inclusive*/

  gtk_progress_bar_set_fraction (GTK_PROGRESS_BAR (progress_bar), fraction);

  /*Use the created fill function every 500 milliseconds*/

  g_timeout_add (500, fill, GTK_PROGRESS_BAR (progress_bar));

  gtk_widget_show_all (window);

}

int

main (int argc, char **argv)

{

  GtkApplication *app;

  int status;

  app = gtk_application_new ("org.gtk.example", G_APPLICATION_FLAGS_NONE);

  g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);

  status = g_application_run (G_APPLICATION (app), argc, argv);

  g_object_unref (app);

  return status;

}