#include <gtk/gtk.h>

static gboolean print_cmd_arg(GApplication *app, GApplicationCommandLine *app_cmd, int *argc)
{
    g_application_activate(app);
    if (*argc > 1)
    {
        char **argv = g_application_command_line_get_arguments(app_cmd, argc);
[nikola@leviathan tmp]$ cat test.c
#include <gtk/gtk.h>

static gboolean print_cmd_arg(GApplication *app, GApplicationCommandLine *app_cmd, int *argc)
{
    g_application_activate(app);
    if (*argc > 1)
    {
        char **argv = g_application_command_line_get_arguments(app_cmd, argc);
        GFile *file = g_file_new_for_commandline_arg(argv[1]);

        if (g_file_query_exists(file, NULL))
        {
            char *text;
            g_file_load_contents(file, NULL, &text, NULL, NULL, NULL);
            g_print("%s", text);
            g_free(text);
            g_object_unref(file);
        }
        else
        {
            g_print("File \'%s\' does not exist.\n", argv[1]);
            g_object_unref(file);
        }
    }
}

static void activation(GtkApplication *app, gpointer user_data)
{
    GtkWidget *window = gtk_application_window_new(app);
    gtk_window_set_default_size(GTK_WINDOW(window), 200, 200);
    gtk_window_set_position(GTK_WINDOW(window), GTK_WIN_POS_CENTER_ALWAYS);
    gtk_window_set_title(GTK_WINDOW(window), "Test");
    g_signal_connect(window, "delete-event", G_CALLBACK(gtk_widget_destroy), NULL);

    GtkWidget *button = gtk_button_new_with_label("Quit");
    g_signal_connect_swapped(button, "clicked", G_CALLBACK(gtk_widget_destroy), window);

    gtk_container_set_border_width(GTK_CONTAINER(window), 10);
    gtk_container_add(GTK_CONTAINER(window), button);

    gtk_widget_show_all(window);
}

int main(int argc, char **argv)
{
    int status = 1234;
    GtkApplication *test = gtk_application_new("this.is.only.a.test", G_APPLICATION_NON_UNIQUE | G_APPLICATION_HANDLES_COMMAND_LINE);
    g_signal_connect(test, "activate", G_CALLBACK(activation), NULL);
    g_signal_connect(G_APPLICATION(test), "command-line", G_CALLBACK(print_cmd_arg), &argc);
    status = g_application_run(G_APPLICATION(test), argc, argv);
    g_print("%d\n", status);
    return status;
}