linux/gcc/gtk2 programming help

Hello everyone, I am new to c programming and I have a question about gtk2 programming on linux using c. I copied the gtk2 helloworld tutorial from their website and compiled it nicely. Here is the code:

Code:

---

#include <gtk/gtk.h>

static void hello( GtkWidget *widget, gpointer  data )
{
    g_print ("Hello World\n");
}

static gboolean delete_event( GtkWidget *widget, GdkEvent  *event, gpointer  data )
{
 

    g_print ("delete event occurred\n");

 
    return TRUE;
}

static void destroy( GtkWidget *widget, gpointer  data )
{
    gtk_main_quit ();
}

int main( int  argc, char *argv[] )
{
 
    GtkWidget *window;
    GtkWidget *button;
   

    gtk_init (&argc, &argv);
   

    window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
   
   
    g_signal_connect (G_OBJECT (window), "delete_event", G_CALLBACK (delete_event), NULL);
   
 
    g_signal_connect (G_OBJECT (window), "destroy", G_CALLBACK (destroy), NULL);
   
 
    gtk_container_set_border_width (GTK_CONTAINER (window), 10);
   
 
    button = gtk_button_new_with_label ("Hello World");
   
//###############################################################################
    g_signal_connect (G_OBJECT (button), "clicked", G_CALLBACK (hello), NULL);
//###############################################################################
   
 
    g_signal_connect_swapped (G_OBJECT (button), "clicked", G_CALLBACK (gtk_widget_destroy), G_OBJECT (window));
   

    gtk_container_add (GTK_CONTAINER (window), button);
   

    gtk_widget_show (button);
   
   
    gtk_widget_show (window);
   
 
    gtk_main ();
   
    return 0;
}

---

I just produces a little dialog box with a button and prints hello world to a terminal when the button is clicked. I would like to split the callback function to a new file to get the hang of multiple c files. But when I try to move the "static void hello" function (at the top of the page) to a new file, I get errors. I am using gcc to compile the two files and make one executable.

How do I compile cleanly?