Defect in XBD 12.2

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        Defect report from : Andrew Josey , The Open Group

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@ page 204 line 7237-7240 section 12.2  comment {ag-ob-synopses}

Problem:

Edition of Specification (Year): 2004

Defect code :  3. Clarification required

This is a request for interpretation of the standard.

Is an implementation of a standard utility permitted to support extensions 
beyond the standard in violation of the Utility Syntax Guidelines when the 
description of the utility says it shall support them?

An example would be an implementation of the head utility supporting
the previously  obsolescent synopsis , head -42 file
rather than head -n 42 file



Action:

Confirmation is sought that an implementation is permitted to have extensions 
so long as the standard form is also accepted
and that the extension is for backwards-compatibility.

The proposed rationale is as follows:

The last paragraph of 1003.2-1992 2.10.2
and XBD 1003.1-2001 2.12 allows utilities to  accept
as extensions other forms that do not match the
guidelines  so long as the standard form is also accepted.

Looking at head I would interpret the situation as follow:

1. head -n 42 filename    
An implementation of the head utility that only accepts this
form would be a strictly conforming implementation.
This form must be used by conforming applications.

2. head -42 filename   
An implementation of the head utility that accepts this form ( and
the form in 1 above) is a conforming implementation with extensions.
The extension violates the guidelines as allowed by 2.12. 
but is clearly for backwards compatibility since its a form that was 
in previous version of the standard.  The intent of removing the obsolescent 
forms of the synopses was not to disallow them to be supported by 
implementations but to downgrade their status of their use in applications from 
conforming application using an obsolescent
feature to non-conforming application.
This form must not be used by conforming application.