Glade-2's "Object" field

["Jim George" <jimgeorge gmail com>]

What is the function of Glade-2's "Object" field in the signals tab in
the properties browser? I initially thought if you put in a variable
name here, it's used in the user parameter passed to the signal
handler. I'm not sure, though, if I need some other magic incantation
on gcc's command line (like -export-dynamic) to get libglade to
recognize the variable.