Thread: segmentation fault?

Hi,
Im new to this forum and I like what i seen so far. Could anyone tell me whats wrong with this program below. I get a segmentation fault when pressing the button.

Code:

#include <gtk/gtk.h>
typedef enum { APPLE, BANANA } Fruit_Type;

typedef struct Fruit {Fruit_Type ft;} Fruit;


void PealAFruit(Fruit_Type fruit)
{
	g_message ("PealAFruit called");
}

static gboolean button_clicked( GtkWidget      *widget, 
                              GdkEventButton *event,
                              gpointer        data)
{
	Fruit *afruit = (Fruit*)data; 

	PealAFruit(afruit->ft);   /*here a segmentation fault */
	return TRUE;
}

int main( int   argc, char *argv[] )
{
    g_message ("start"); 
    GtkWidget *window;
    GtkWidget *button;
    Fruit     *afruit;

    gtk_init (&argc, &argv);

    window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    button = gtk_button_new_with_label ("Hello World");

    if ( (afruit = (Fruit*)g_malloc(sizeof(Fruit))) != NULL) 
	{
		afruit->ft = APPLE;
		g_signal_connect (G_OBJECT (button), "clicked",
		      G_CALLBACK (button_clicked), afruit);
	}

    gtk_container_add (GTK_CONTAINER (window), button);

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

ok I run ddd and I se data is a NULL-pointer. SO im on the track.

The return value i null so I guess I alocat the memory badly. I just want to send a pointer of the struct to the function. Should not be this hard. Im trying to check it in GDB and DDD. But since I am new to c and these programs its hard.

How do I print a pointervalue, the addressto check that I send a value?