Introduced in the 1995 ANSI M[UMPS] language standard.
This variable indicates whether the current block of code was called as an extrinsic function, or as a subroutine.
This special variable is mainly used in error-trapping
conditions. Its value tells whether the current DO level was
reached by means of a subroutine call (DO xxx) or
by a function call (SET variable=$$xxx).
A typical way of exiting from an error trap is:
QUIT:$QUIT "" QUIT
This document is © Ed de Moel, 1995-2005.
It is part of a book by Ed de Moel that is published under the
title "M[UMPS] by Example" (ISBN 0-918118-42-5).
Printed copies of the book are no longer available.
This document describes the various special variables that are defined in the M[UMPS] language standard (ANSI X11.1, ISO 11756).
The information in this document is NOT authoritative
and subject to be modified at any moment.
Please consult the appropriate (draft) language standard for an
authoritative definition.
In this document, information is included that will
appear in
future standards.
The MDC cannot guarantee that these 'next'
standards will indeed appear.