ONWCHAR
ONWCHAR returns a widechar(1) string containing the widechar that caused the CONVERSION condition to be raised.
It is in context in an ON-unit (or any of its dynamic descendants)
for the CONVERSION condition or for the ERROR or FINISH condition
raised as the implicit action for the CONVERSION condition.
If the ONWCHAR built-in function is used out of context, a widechar blank is returned.