NAME

getpriority, setpriority − get/set program scheduling priority

SYNOPSIS

prio = getpriority(which, who)
int prio, which, who;

setpriority(which, who, prio)
int which, who, prio;

DESCRIPTION

The scheduling priority of the process, process group, or user, as indicated by which and who is obtained with the getpriority call and set with the setpriority call.  Which is one of:

PRIO_PROCESS0/∗ process ∗/
PRIO_PGRP  1/∗ process group ∗/
PRIO_USER  2/∗ user id ∗/

and who is interpreted relative to which (a process identifier for PRIO_PROCESS, process group identifier for PRIO_PGRP, and a user ID for PRIO_USER).  Prio is a value in the range −20 to 20.  The default priority is 0; lower priorities cause more favorable scheduling. 

The getpriority call returns the highest priority (lowest numerical value) enjoyed by any of the specified processes.  The setpriority call sets the priorities of all of the specified processes to the specified value.  Only the super-user may lower priorities. 

RETURN VALUE

Since getpriority can legitimately return the value −1, it is necessary to check the external variable errno, which is set to an non-zero error code when there is an error to determine if a −1 is an error or a legitimate value.  The setpriority call returns 0 if there is no error, or −1 if there is. 

ERRORS

To be supplied. 

SEE ALSO

nice(1), fork(2)

Sun System Release 0.3  —  25 April 1983