[Glade] button problem

Question

Hi,

i'm using glade to designa a interface for my program written in C but i have some problem with the buttons.

Can someone explain me how to set in glade an action for a button?

i mean, i wrote a function in my code but i don't know how to associate it to the graphic... i set i the Signal box the GtkButton activate and i chose "on_button_activate" and in "user data" i put the name of my function but when i copile it this is the terminal answare:

chris@chris-laptop:~/Scrivania$ ./provaGrafica 

(provaGrafica:3139): Gtk-WARNING **: Could not lookup object funzione_esporta on signal activate of object button4

(provaGrafica:3139): Gtk-WARNING **: Could not find signal handler 'on_button4_activate'
chris@chris-laptop:~/Scrivania$

and obviusly the button do not work

thanks