[newbie] dont understand signal_connect

[Jean Michel LECONTE <Jean-Michel Leconte lambda-systems com>]

i have a window (his name is window1) 
how to do if i want that when a guy push the cross to close window1, the 
program executes  the function  call_pl_term(goal);

im in this function:

Bool set_signal_connect(int internal_number,char *signal,PlTerm *goal)
{





    return TRUE;
}


Thanks a lot .