GTK Markup label example

pango.c

label = gtk_label_new(NULL);
gtk_widget_set_hexpand(label, TRUE);
gtk_label_set_markup(GTK_LABEL(label),
                     "Hello, World\n"
					 "<span size='large'>This is a test.</span?");
gtk_label_set_justify(GTK_LABEL(label), GTK_JUSTIFY_CENTER);
gtk_grid_attach(GTK_GRID(mainGrid), label, 0, 0, 1, 1);
gtk_widget_show(label);