show window after a period of time

#include <gtk/gtk.h>

void close_window(GtkWidget* widget, gpointer data)
{
    gtk_window_close(widget);
}

void show_simple_window()
{
    GtkApplication* app;
    GtkWidget* window;

    GtkWidget* grid;
    GtkWidget* button;
    app = gtk_application_new("org.gtk.example", G_APPLICATION_FLAGS_NONE);

    /* create a new window, and set its title */
    window = gtk_application_window_new(app);
    gtk_window_set_title(GTK_WINDOW(window), "Window");
    gtk_container_set_border_width(GTK_CONTAINER(window), 10);

    /* Here we construct the container that is going pack our buttons */
    grid = gtk_grid_new();

    /* Pack the container in the window */
    gtk_container_add(GTK_CONTAINER(window), grid);

    button = gtk_button_new_with_label("Button 1");
    //g_signal_connect(button, "clicked", G_CALLBACK(print_hello), NULL);

    /* Place the first button in the grid cell (0, 0), and make it fill just 1 cell horizontally and vertically (ie no spanning) */
    gtk_grid_attach(GTK_GRID(grid), button, 0, 0, 1, 1);

    button = gtk_button_new_with_label("Button 2");
    //g_signal_connect(button, "clicked", G_CALLBACK(print_hello), NULL);

    /* Place the second button in the grid cell (1, 0), and make it fill just 1 cell horizontally and vertically (ie no spanning) */
    gtk_grid_attach(GTK_GRID(grid), button, 1, 0, 1, 1);
    button = gtk_button_new_with_label("Quit");
    g_signal_connect_swapped(button, "clicked", G_CALLBACK(close_window), window); //gtk_widget_destroy

    /* Place the Quit button in the grid cell (0, 1), and make it span 2 columns. */
    gtk_grid_attach(GTK_GRID(grid), button, 0, 1, 2, 1);

    /* Now that we are done packing our widgets, we show them all
     * in one go, by calling gtk_widget_show_all() on the window.
     * This call recursively calls gtk_widget_show() on all widgets
     * that are contained in the window, directly or indirectly.
     */
    gtk_widget_show_all(window);
    g_object_unref(app);
}

void setTimeout(int milliseconds)
{
    // If milliseconds is less or equal to 0
    // will be simple return from function without throw error
    if (milliseconds <= 0) {
        fprintf(stderr, "Count milliseconds for timeout is less or equal to 0\n");
        return;
    }

    // a current time of milliseconds
    int milliseconds_since = clock() * 1000 / CLOCKS_PER_SEC;

    // needed count milliseconds of return from this timeout
    int end = milliseconds_since + milliseconds;

    // wait while until needed time comes
    do {
        milliseconds_since = clock() * 1000 / CLOCKS_PER_SEC;
    } while (milliseconds_since <= end);
}

void repetitive_task()
{
    int delay = 5;
start_point:
    // counter downtime for run a rocket while the delay with more 0
    do {
        // erase the previous line and display remain of the delay
        printf("\n\033[ATime left for open new window: %d\n", delay);

        // a timeout for display
        setTimeout(1000);

        // decrease the delay to 1
        delay--;

    } while (delay >= 0);

    show_simple_window();
    delay = 5;
    goto start_point;
}

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

    repetitive_task();
    //show_simple_window();

    gtk_main();
    return 0;
}