nice.2

unix v7是最后一个广泛发布的研究型UNIX版本

.TH NICE 2 
.SH NAME
nice \- set program priority
.SH SYNOPSIS
.B nice(incr)
.SH DESCRIPTION
The scheduling
priority of the process is augmented by
.IR incr .
Positive priorities get less
service than normal.
Priority 10 is recommended to users
who wish to execute long-running programs
without flak from the administration.
.PP
Negative increments are ignored except on behalf of 
the super-user.
The priority is limited to the range
\-20 (most urgent) to 20 (least).
.PP
The priority of a process is
passed to a child process by
.IR fork (2).
For a privileged process to return to normal priority
from an unknown state,
.I nice
should be called successively with arguments
\-40 (goes to priority \-20 because of truncation),
20 (to get to 0),
then 0 (to maintain compatibility with previous versions
of this call).
.SH "SEE ALSO"
nice(1)
.SH ASSEMBLER
(nice = 34.)
.br
(priority in r0)
.br
.B sys nice