Button for 1977 Button for 1984 Button for 1990 Button for 1995 Button for MDC Button for notes Button for examples
Left Hand Pointer

Error Code M21

M[UMPS] by Example

Right Hand Pointer

M21, Algorithm specification invalid

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

When a label occurs with a parameter list (a formallist), and the same name occurs multiple times in this parameter list, this error will occur.

Note that it does make sense to be able to have the same name multiple times in a parameter list when a function or subroutine is invoked (actuallist), but not in the formal parameter list at the start of that function or subroutine.

Set SUM=$$ADD(A,A)
is a valid function call.

ADD(X,X) Quit X+X
will cause this error to occur; most likely, this should have been
ADD(X,Y) Quit X+Y

Button for 1977 Button for 1984 Button for 1990 Button for 1995 Button for MDC Button for notes Button for examples

Copyright © Standard Documents; 1977-2017 MUMPS Development Committee;
Copyright © Examples: 1995-2017 Ed de Moel;
Copyright © Annotations: 2003-2017 Jacquard Systems Research.

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 29-Nov-2011, 22:30:57 .

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