Subject: Re: [SWIPL] PL_exception() side-effect?

From: Jan Wielemaker <[email-masked]>
Date: Sun, 25 Feb 2001 10:34:51 +0100

> If a call to PL_exception() returns a non-zero term reference, is
> the exception no longer registered?

PL_exception() returns non-zero if an exception is pending and the
return-value is a term-reference holding the exception-term.  If
it returns zero, no exception is pending.

An interesting question is whether it is possible for PL_exception()
to return an invalid term-reference.  The value is guaranteed to be
trustworthy after a call to Prolog returns failure.  It can be destroyed
using one of the foreign-frame rewind functions.

Maybe you should be clearer on how you wish to use it.

	--- Jan