GTK+ Forums

srikanth · Familiar Face Joined: 14 Nov 2006 Posts: 7

Hello ,

I am trying to use structures

Code: (Plaintext)
1 2 3 4 5	typedef struct testing { GtkWidget checkbutton6; GtkWidget checkbutton7; GtkWidget *checkbutton8; }ex;

Code: (Plaintext)
1	ex w = (ex) g_malloc (sizeof (ex));

This is the callback function

Code: (Plaintext)
1 2 3	g_signal_connect ((gpointer) druidpagestandard2, "prepare", G_CALLBACK (on_druidpagestandard2_prepare), (gpointer) w);

In callbacks.c function definition

Code: (Plaintext)
1 2 3 4 5 6 7 8 9 10 11	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: (Plaintext)
1 2 3 4 5	callbacks.c: In function ‘on_druidpagestandard2_prepare’: callbacks.c:54: warning: dereferencing ‘void ’ pointer callbacks.c:54: error: request for member ‘checkbutton6’ in something not a structure or union make: ** [callbacks.o] Error 1

What am i doing wrong ?

Thanks.

cnu_sree · GTK+ Geek Joined: 06 Oct 2006 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 · Familiar Face Joined: 14 Nov 2006 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 Post subject:

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: (Plaintext)
1	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.