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.

http://developer.gnome.org/doc/API/2...t-Signals.html
A quick browse through the API suggests that g_signal_new() might be a pre-requisite call.

g_signal_connect also returns a value - is it valid?

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?

Return value from what?

Read the manual, if g_signal_connect() is returning NULL, then I'm guessing it means the whole thing failed because you need to call g_signal_new() first, and perhaps some other stuff as well.

It's like calling fgets() without calling fopen(). If you don't do all the required stuff first, then the call itself makes no sense.