From ajosey@rdg.opengroup.org Thu Apr 17 10:14:56 1997 Received: from mailgate.rdg.opengroup.org (mailgate.rdg.opengroup.org [192.153.166.4]) by dkuug.dk (8.6.12/8.6.12) with SMTP id KAA26225 for ; Thu, 17 Apr 1997 10:14:54 +0200 Received: by mailgate.rdg.opengroup.org; id AA06289; Thu, 17 Apr 1997 09:15:05 GMT Message-Id: <9704170915.AA06289@mailgate.rdg.opengroup.org> Received: by mailhome.rdg.opengroup.org (1.36.108.10/16.2) id AA01842; Thu, 17 Apr 1997 09:11:59 +0100 From: ajosey@rdg.opengroup.org (Andrew Josey) Date: Thu, 17 Apr 1997 09:11:59 +0100 In-Reply-To: Andrew Josey's message as of Apr 17, 9:04am. Reply-To: ajosey@rdg.opengroup.org (Andrew Josey) X-Mailer: Mail User's Shell (7.2.5 10/14/92) To: sc22wg15@dkuug.dk Subject: 1003.1b-1993 Finalised PASC Interps Attached are the finalised PASC 1003.1b-1993 interpretations since October 1996. These are being circulated in accordance with Action 9610-60 . regards Andrew ----- Andrew Josey PASC Functional Chair Interpretations The Open Group Apex Plaza,Forbury Road, Reading,Berks.RG1 1AX,England Tel: +44 118 9508311 ext 2250 Fax: +44 118 9500110 Email: a.josey@opengroup.org #--------------------------------CUT HERE------------------------------------- #! /bin/sh # # This is a shell archive. Save this into a file, edit it # and delete all lines above this comment. Then give this # file to sh by executing the command "sh file". The files # will be extracted into the current directory owned by # you with default permissions. # # The files contained herein are: # # -rw-r--r-- 1 ajosey other 4068 Mar 18 08:28 pasc-1003.1b-12.html # echo 'x - pasc-1003.1b-12.html' if test -f pasc-1003.1b-12.html; then echo 'shar: not overwriting pasc-1003.1b-12.html'; else sed 's/^X//' << '________This_Is_The_END________' > pasc-1003.1b-12.html X X X[Ref: pasc-1003.1b-12] Topic: messages X X X

XPASC Interpretation Ref: pasc-1003.1b-12
Topic: messages X

X

X

XThis is an unapproved interpretation of PASC P1003.1b-1993. X

XUse of the information contained in this unapproved document is at your Xown risk. X

XLast update: 18 March,1997 X

X
X								1003.1b-93  #12
X
X _____________________________________________________________________________
X
X	Interpretation Number:	XXXX
X	Topic:               messages
X	Relevant Sections:   2.2.2.65, 2.2.2.66
X
XInterpretation Request:
X-----------------------
X
X	From: Andrew Josey (on behalf of the X/Open Base Working group)
X
X
XPart 1. Interpretation Request for:
X   IEEE Std 1003.1b-1993 as contained in:
X   ISO/IEC 9945-1:1996(E), ANSI/IEEE Std. 1003.1, 1996 Edition.
X   Subsection 2.2.2.65, Page 20, Line 298.
X
XQuestion:
XThe sentence "A message consists of a fixed-size message buffer." seems
Xcontradictory to the description of a message presented in subsections 15.2.4 
Xand 15.2.5 (Interfaces to send and receive a message). 
X
XWhen a message is sent, the size of the message buffer is not fixed, 
Xbut is user specified for each message sent. When a message is received, 
Xthe size of the buffer into which the message is to be fetched is 
Xeffectively fixed by the mq_msgsize attribute of the message queue 
X(although the user may specify a larger buffer, with no
Xapparent benefit), but each message so received is of variable size, with the
Xsize returned by mq_receive().
X
XTherefore, can it be that a message "consists" of a fixed-size message buffer?
X
XSuggested Correction:
XChange the sentence to "The size of a message is variable but limited to a
Xfixed maximum size established at the time the associated message queue is
Xcreated.
X
X-------------------------------------------------------------------------------
XPart 2. Interpretation Request for:
X   IEEE Std 1003.1b-1993 as contained in:
X   ISO/IEC 9945-1:1996(E), ANSI/IEEE Std. 1003.1, 1996 Edition.
X   Subsection 2.2.2.66, Page 20, Line 301-302.
X
XQuestion:
XThe sentence "Messages may be removed in the order in which they were added or
Xin priority order." implies (because of the "or") that it is the user's option
Xas to how messages are removed, independent of how they were queued. This is
Xcontradictory to the way messages are described as queued in section 15.2.4 and
Xreceived in section 15.2.5. Both of these subsections are clear that messages
Xare queued FIFO within priority, and may be removed only in the order found in
Xthe queue (i.e. oldest of the highest priority messages first). There is no
Xoption to remove messages in the order they were added if they were queued with
Xdifferent priorities.
X
XTherefore, is the sentence quoted above technically correct?
X
XSuggested Correction:
XChange the sentence to "When all messages in a message queue are of the same
Xpriority, messages are removed from the queue in the order in which they were
Xadded to the queue. When messages in a message queue are of different
Xpriorities, messages are removed in priority order, first-in-first-out (FIFO)
Xwithin the same priority.
X
XInterpretation response
X------------------------
XThe standard is very clear in section 15.2.4 lines 255-260 on the
Xprecise ordering of the messages.  The definition allows this particular
Xbehavior and notes that the precise characteristics are determined by
Xthe interface and characteristics of the queue.  It is the view of the
Xinterpretations committee that no further clarification is needed.
X                                                                   
X
XRationale
X-------------
XThe definition is clear enough without going into the details of the
Xprecise order that is the current interface.  Since additional
Xinterfaces may be defined in the future, it is not viewed as advisable
Xto unnecessarily constrain the definition.
XForwarded to Interpretations group: Dec 9 1996
XFinalised: 26th Feb 1997
X
X ________This_Is_The_END________ if test `wc -l < pasc-1003.1b-12.html` -ne 102; then echo 'shar: pasc-1003.1b-12.html was damaged during transit (should have been 102 bytes)' fi fi ; : end of overwriting check exit 0