#GtkMessageDialog presents a dialog with some message text. It’s simply a convenience widget; you could construct the equivalent of #GtkMessageDialog from #GtkDialog without too much effort, but #GtkMessageDialog saves typing.

One difference from #GtkDialog is that #GtkMessageDialog sets the #GtkWindow:skip-taskbar-hint property to true, so that the dialog is hidden from the taskbar by default.

The easiest way to do a modal message dialog is to use gtk.dialog.Dialog.run, though you can also pass in the gtk.types.DialogFlags.Modal flag, gtk.dialog.Dialog.run automatically makes the dialog modal and waits for the user to respond to it. gtk.dialog.Dialog.run returns when any dialog button is clicked.

An example for using a modal dialog:

GtkDialogFlags flags = GTK_DIALOG_DESTROY_WITH_PARENT;
dialog = gtk_message_dialog_new (parent_window,
                                 flags,
                                 GTK_MESSAGE_ERROR,
                                 GTK_BUTTONS_CLOSE,
                                 "Error reading “%s”: %s",
                                 filename,
                                 g_strerror (errno));
gtk_dialog_run (GTK_DIALOG (dialog));
gtk_widget_destroy (dialog);

You might do a non-modal #GtkMessageDialog as follows:

An example for a non-modal dialog:

GtkDialogFlags flags = GTK_DIALOG_DESTROY_WITH_PARENT;
dialog = gtk_message_dialog_new (parent_window,
                                 flags,
                                 GTK_MESSAGE_ERROR,
                                 GTK_BUTTONS_CLOSE,
                                 "Error reading “%s”: %s",
                                 filename,
                                 g_strerror (errno));

// Destroy the dialog when the user responds to it
// (e.g. clicks a button)

g_signal_connect_swapped (dialog, "response",
                          G_CALLBACK (gtk_widget_destroy),
                          dialog);

GtkMessageDialog as GtkBuildable

The GtkMessageDialog implementation of the GtkBuildable interface exposes the message area as an internal child with the name “message_area”.