Standards Update, IEEE 1003.2: Shell and tools

[David A Willcox]

Submitted-by: willcox at urbana.mcd.mot.com (David A Willcox)

In article <530 at usenix.ORG> jsh at usenix.org (Jeffrey S. Haemer) writes:

>A few utilities remain contentious:

>   + nice, renice: These require underlying functionality absent from
>     POSIX.1, although POSIX.4 has setscheduler(), which allows
>     applications to set priority and scheduling algorithms.

A point of clarification:  These utilities, as defined in 1003.2a,
do NOT require any functionality that is not in 1003.1.  Both can be
implemented on a bare-bones 1003.1 system as having no effect on 
execution priority.  The following, for example, is a valid
shell script implementation of nice:

	case $1 in
	    -n) shift;shift;;
	    -*  shift;;
	esac
	exec $*

renice is a little more complicated, but not much.  (It should just have
to check for valid arguments.)

So saying that you can't implement this on a 1003.1 system is not only
a red herring, it simply isn't true.

Providing these utilities allows well-mannered applications to make use
of the priority manipluation features that are already provided by most
implementations.

David A. Willcox		"Just say 'NO' to universal drug testing"
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Volume-Number: Volume 21, Number 122