Re: How can I use g_signal_connect() to pass a gponiter parameter

[Magnus Myrefors <tkv764x tninet se>]

frantishek wrote:

My code does it just by the book:

void setPermission(GtkWidget *window, gpointer p)
{
	g_print("%s\n", (gchar*) p);
}

radio1 = gtk_radio_button_new_with_label (NULL, "First");
radio2 = gtk_radio_button_new_with_label_from_widget (GTK_RADIO_BUTTON
(radio1), "Second");
radio3 = gtk_radio_button_new_with_label_from_widget (GTK_RADIO_BUTTON
(radio1), "Third");
g_signal_connect_swapped (G_OBJECT (radio1), "clicked", G_CALLBACK
(setPermission), (gpointer) "Clicked 0");    
g_signal_connect_swapped (G_OBJECT (radio2), "clicked", G_CALLBACK
(setPermission), (gpointer) "Clicked 1");    
g_signal_connect_swapped (G_OBJECT (radio3), "clicked", G_CALLBACK
(setPermission), (gpointer) "Clicked 2");    

Yet, when I select any of these radio buttons, it prints out some garbage
(the same for each button).

Any idea why?


learning_gtk wrote:
  

I hope to use  g_signal_connect() to pass a gchar* parameter like this:

gchar* radio1= "Radio1"; //it is global variable
gchar* radio2= "Radio2";
gchar* radio3= "Radio3";

void item_radio_print1(gpointer* data)
{
        g_print("This is the radio %s\n", (gchar *)data);
}

g_signal_connect(G_OBJECT(item_radio1), "activate",
                     GTK_SIGNAL_FUNC(item_radio_print1),
(gpointer*)radio1);
g_signal_connect(G_OBJECT(item_radio2), "activate",
                     GTK_SIGNAL_FUNC(item_radio_print1),
(gpointer*)radio2);
g_signal_connect(G_OBJECT(item_radio3), "activate",
                     GTK_SIGNAL_FUNC(item_radio_print1),
(gpointer*)radio3);

But, those strings can not be printed.

Please help me. Thanks!

    

Hi,

  You seem to be printing out a pointer and not what the pointer is pointing to.
  If you want to print the whole string f.ex. "Radio1" you should try with another type,
  since gchar* just points to a gchar . 
  You could use  gchar  radio1[]  or  const gchar *radio1 since these types are stored
  differently in memory than a gchar *.

magnusm