WG15 Defect Report Ref: 9945-2-72
Topic: renice

This is an approved interpretation of 9945-2:1993.


Last update: 1997-05-20



	Topic:			renice
	Relevant Sections:	5.24

Defect Report:

	Date: Wed, 3 Aug 1994 18:35:48 -0700
	From: Fred Zlotnick <fred@mindcraft.com>

I would like to an request official, binding interpretation from the
WG15 concerning the following points in ISO/IEC 9945-2:1993 (POSIX.2).

POSIX.2 subclause 5.24 specifies the semantics of the "renice"
utility.  During the development of a conformance test for POSIX.2
questions about this utility have arisen.  In subclause 5.24.2 the
utility's behavior is described as follows:

	The renice utility shall request that the system scheduling
	priorities (see 2,2,2,177) of one or more running processes
	be changed.

Further, in subclause 5.24.8 the exit status of renice is specified as

	 0	Successful completion
	>0	An error occurred

Is it conforming for an implementation to return 0, meaning that the
request is noted and is syntactically correct, but to ignore it or to
honor it partially?  That is, can a system return 0 but not change the
specified process's priority?  Can a system return 0 and change the
process's priority, but not to the extent requested?

Further, is there any guarantee that the priority schedule change, if
honored, will persist for any period?  For example, can a shell script
rely on using a call such as

	ps -o nice -p <pid>

to determine whether the scheduling priority of process <pid> has been
changed in accordance with the request?

Thank you for your attention to this matter.

Interpretation Response:

Question 1: yes

Question 2: yes

Question 3: yes, the standard clearly states this behaviour on page 594,
lines 3796-3800.

Question 4,
Question 5 : 
The standard does not speak to this issue, and as such no conformance 
distinction can be made between alternative implementations based on this.  
This is being refered to the sponsor.


Forwarded to Interpretations group: 4 Aug 94

Proposed resolution sent for review: 19th Nov 94
Resolved: 10th Dec 94