PUI button callbacks

if there is anybody who is familiar with the picoscopic user interface could they please help. "When PUI calls a widget callback, it passes to it the address of the widget whose activation caused the callback"
so why does the following code not print "yes..." when i press the one_but button. It prints "no...." instead.

void button_cb( puObject *ob)
{
if(ob==one_but)
{
fprintf ( stderr, "yes im working.\n" ) ;
}
else
{
fprintf ( stderr, "no im not working.\n" ) ;
}
}