manual page distributed with 4.2BSD

SCCS-vsn: lib/libc/sys/getpriority.2 5.1

diff --git a/usr/src/lib/libc/sys/getpriority.2 b/usr/src/lib/libc/sys/getpriority.2
index 92ab701..3d78e49 100644 (file)
--- a/usr/src/lib/libc/sys/getpriority.2
+++ b/usr/src/lib/libc/sys/getpriority.2
@@ -2,45 +2,97 @@
 .\" All rights reserved.  The Berkeley software License Agreement
 .\" specifies the terms and conditions for redistribution.
 .\"
 .\" All rights reserved.  The Berkeley software License Agreement
 .\" specifies the terms and conditions for redistribution.
 .\"

-.\"    @(#)getpriority.2       4.1 (Berkeley) %G%
+.\"    @(#)getpriority.2       5.1 (Berkeley) %G%

 .\"
 .\"

-.TH NICE 2 
+.TH GETPRIORITY 2 "18 July 1983"

 .UC 4
 .SH NAME
 .UC 4
 .SH NAME

-nice \- set program priority
+getpriority, setpriority \- get/set program scheduling priority

 .SH SYNOPSIS
 .SH SYNOPSIS

-.B nice(incr)
+.nf
+.ft B
+#include <sys/resource.h>
+.PP
+.ft B
+#define PRIO_PROCESS   0       /* process */
+#define PRIO_PGRP              1       /* process group */
+#define PRIO_USER              2       /* user id */
+.PP
+.ft B
+prio = getpriority(which, who)
+int prio, which, who;
+.PP
+.ft B
+setpriority(which, who, prio)
+int which, who, prio;
+.fi

 .SH DESCRIPTION
 The scheduling
 .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.
+priority of the process, process group, or user, as indicated by
+.I which
+and
+.I who
+is obtained with the
+.I getpriority
+call and set with the
+.I setpriority
+call.
+.I Which
+is one of PRIO_PROCESS, PRIO_PGRP, or PRIO_USER, and 
+.I who
+is interpreted relative to 
+.I which
+(a process identifier for PRIO_PROCESS, process group
+identifier for PRIO_PGRP, and a user ID for PRIO_USER).
+.I Prio
+is a value in the range \-20 to 20.  The default priority is 0;
+lower priorities cause more favorable scheduling.

 .PP
 .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).
+The
+.I getpriority
+call returns the highest priority (lowest numerical value)
+enjoyed by any of the specified processes.  The
+.I setpriority
+call sets the priorities of all of the specified processes
+to the specified value.  Only the super-user may lower priorities.
+.SH "RETURN VALUE
+Since
+.I getpriority
+can legitimately return the value \-1, it is necessary
+to clear the external variable \fIerrno\fP prior to the
+call, then check it afterward to determine
+if a \-1 is an error or a legitimate value.
+The
+.I setpriority
+call returns 0 if there is no error, or
+\-1 if there is.
+.SH ERRORS
+.I Getpriority
+and
+.I setpriority
+may return one of the following errors:
+.TP 15
+[ESRCH]
+No process(es) were located using the 
+.I which
+and
+.I who
+values specified.
+.TP 15
+[EINVAL]
+.I Which
+was not one of PRIO_PROCESS, PRIO_PGRP, or PRIO_USER.

 .PP
 .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).
+In addition to the errors indicated above,
+.I setpriority
+may fail with one of the following errors returned:
+.TP 15
+[EACCES]
+A process was located, but neither its effective nor real user
+ID matched the effective user ID of the caller.
+.TP 15
+[EACCES]
+A non super-user attempted to change a process
+priority to a negative value.

 .SH "SEE ALSO"
 nice(1), fork(2), renice(8)
 .SH "SEE ALSO"
 nice(1), fork(2), renice(8)

-.SH "ASSEMBLER (PDP-11)"
-(nice = 34.)
-.br
-(priority in r0)
-.br
-.B sys nice