Trigger question

["Lance Gillespie" <lgillespie@xxxxxxxx>]

How can I tell the user why the trigger program has
rejected the attempted update?

I hope the answer is something like the trigger
program determines what is wrong, sends a 
message up the stack, sets the flag that causes
the update or write or delete to fail and returns.

The RPG program that attempted the operation
checks %error and re-displays the data entry
screen with the reason displayed as a message
on line 25.  This would mean that the update
program does not know why the update failed
and relies on the user to read the message.

Is this the way it works?  And if so, how does
the trigger program send the message and 
how does the update program display it?

TIA, Lance

Lance Gillespie
Coachella Valley Water District