☜	Error Code M45 M[UMPS] by Example					☞

M45, Invalid GOTO reference

Introduced in the 1995 ANSI M[UMPS] language standard.

One addition in the 1990 ANSI M[UMPS] language standard is that it has become possible to define blocks of code that can only be entered at one point by means of an argumentless Do command. Within such blocks, deeper nested blocks may be defined. Within one such block, control may be transferred using a Goto command.

When a Goto command is executed, and the destination of the executed argument is a line within an ‘indented’ block, and the Goto command does not originate from a line at the same level of indentation in the same ‘indented’ block, this error will occur.

Note: in his article GOTO Command Considered Harmful (March 1968, Communications of the ACM, Volume 11/3), Edsger W. Dijkstra warns against a certain improper usage of Goto commands. This restriction in the language helps to prevent such improper usage.

Copyright © Standard Documents; 1977-2024 MUMPS Development Committee;
Copyright © Examples: 1995-2024 Ed de Moel;
Copyright © Annotations: 2003-2008 Jacquard Systems Research
Copyright © Annotations: 2008-2024 Ed de Moel.

The information in this page is NOT authoritative and subject to be modified at any moment.
Please consult the appropriate (draft) language standard for an authoritative definition.

Some specifications are "approved for inclusion in a future standard". Note that the MUMPS Development Committee cannot guarantee that such future standards will indeed be published.

This page most recently updated on 16-Nov-2023, 14:47:46.

For comments, contact Ed de Moel (demoel@jacquardsystems.com)