Using Structures

srikanth · **Joined:** Tue Nov 14, 2006 6:06 am **Posts:** 7

Hello ,

I am trying to use structures

Code:

typedef struct testing {
          GtkWidget *checkbutton6;
          GtkWidget *checkbutton7;
          GtkWidget *checkbutton8;
  }ex;

Code:

ex *w = (ex*) g_malloc (sizeof (ex));

This is the callback function

Code:

g_signal_connect ((gpointer) druidpagestandard2, "prepare",
                    G_CALLBACK (on_druidpagestandard2_prepare),
                    (gpointer) w);

In callbacks.c function definition

Code:

void
on_druidpagestandard2_prepare          (GnomeDruidPage  *gnomedruidpage,
                                        GtkWidget       *widget,
                                        gpointer        w)

{
        gint box_status;
         printf("\n");
        box_status = gtk_toggle_button_get_active    ((GtkToggleButton *) w->checkbutton6);

When i compile the program i am getting following error

Code:

callbacks.c: In function â€˜on_druidpagestandard2_prepareâ€™:
callbacks.c:54: warning: dereferencing â€˜void *â€™ pointer
callbacks.c:54: error: request for member â€˜checkbutton6â€™ in something not a structure or union
make: *** [callbacks.o] Error 1

What am i doing wrong ?

Thanks.

cnu_sree · **Joined:** Fri Oct 06, 2006 6:37 am **Posts:** 57

void
on_druidpagestandard2_prepare (GnomeDruidPage *gnomedruidpage,
GtkWidget *widget,
gpointer w)

{
ex *x = (ex *) w;
gint box_status;
printf("\n");
box_status = gtk_toggle_button_get_active ((GtkToggleButton *)->checkbutton6);
}
i too faced the ssame problem after adding the line my problem is solved
so try this

srikanth · **Joined:** Tue Nov 14, 2006 6:06 am **Posts:** 7

tried it did not work . I forgot to mention that i am using glade 2 so, i am making call from interface.c to callback.c .

Thanks.

openldev · **Posted:** Mon Nov 20, 2006 4:59 pm

First, when using Glade, you should use Libglade to dynamically load the user interface with the GladeXML object. Source code generation is depreciated and takes up a lot of space.

Second, you are trying to retrieve a member from a void pointer, which is what cru_sree recommended. He just forgot to add the 'x' like so:

Code:

box_status = gtk_toggle_button_get_active (GTK_TOGGLE_BUTTON (x->checkbutton6));

Also, GTK+ provides functions like GTK_TOGGLE_BUTTON() and GTK_WIDGET() for casting. Use them because they are provided by GObject. Either way will work, but this is the correct way.

GTK+ Forums

Using Structures

Who is online