wdhandler is the main message handler, but other handlers may be used if appropriate. There are essentially three alternatives:
wdhandler with your own definition. This gives you complete control over the way you respond to events.
wd command phandler. For example, when the following form is run, any event specific to it will invoke the sentence: abc_event 0 :
wd 'pc abc;pshow;ptop' wd 'phandler "abc_event 0"' abc_event=: wdinfo bind 'abc form handler'
wd command wait, described below.