setpriority(2) DG/UX 5.4R3.00 setpriority(2)
NAME
setpriority - set process scheduling priority
SYNOPSIS
#include <sys/resource.h>
int setpriority (which, who, prio)
int which;
int who;
int prio;
where:
which How the argument who is to be interpreted in identifying
one or more processes whose priorities will be set:
PRIO_PROCESS, PRIO_PGRP, or PRIO_USER
who Identifier of one or more processes whose priorities will
be set: a process ID, a process group ID, or user ID,
depending on the value of which
prio The new priority value
DESCRIPTION
One or more processes are identified by the combination of the
arguments which and who. If which is PRIO_PROCESS, who is
interpreted as a process ID and a single process is identified. If
which is PRIO_PGRP, who is interpreted as a process group ID, and all
processes that are members of that group are identified. If which is
PRIO_USER, who is interpreted as a user ID, and all processes with an
effective user id of who are identified. A who value of 0 is
interpreted as the calling process's process ID, process group ID,
and effective-user-id, respectively, for the three cases listed. For
example, all processes in the calling process's process group may be
identified with which set to PRIO_PGRP and who set to zero.
The setpriority call sets the priorities of all the identified
processes to prio, subject to the access control constraints
described below. The access checks are applied to each process in
the identified set. If one or more processes fail the checks,
setpriority still changes the priority of those processes that pass
the checks, but the error return value will be given.
ACCESS CONTROL
In order to set a process's priority to a larger numerical value
(less favorable scheduling) or leave it unchanged, the calling
process must have an effective-user-id that is 0 or that matches the
target process's effective-user-id.
In order to set a process's priority to a smaller numerical value,
the calling process must have an effective-user-id that is 0.
RETURN VALUE
0 Successful completion.
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setpriority(2) DG/UX 5.4R3.00 setpriority(2)
-1 An error occurred. errno is set to indicate the error.
DIAGNOSTICS
Errno may be set to one of the following error codes:
ESRCH Using the which and who values specified, no processes were
located at all, or if any processes were located, none
passed the access checks.
EINVAL Which was not one of PRIO_PROCESS, PRIO_PGRP, or PRIO_USER.
EACCES One or more (but not all) of the processes in the
identified set did not pass the access checks described
above.
SEE ALSO
fork(2), nice(2).
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