|GETPRIORITY(2)||System Calls Manual||GETPRIORITY(2)|
which, id_t who,
getpriority() call and set with the
setpriority() call. which is one of
PRIO_USER, 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). A zero value of who denotes the current process, process group, or user. prio is a value in the range -20 to 20. The default priority is 0; lower priorities cause more favorable scheduling.
getpriority() call returns the highest
priority (lowest numerical value) enjoyed by any of the specified processes.
setpriority() call sets the priorities of all of
the specified processes to the specified value. Priority values outside the
range -20 to 20 are truncated to the appropriate limit. Only the superuser
may lower priorities.
getpriority() can legitimately return the value -1, it is necessary to clear the external variable errno prior to the call, then check it afterward 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.
setpriority() will fail if:
setpriority() will fail
setpriority() functions conform to IEEE Std 1003.1-2008 (“POSIX.1”).
nice() system call, appeared in Version 3 AT&T UNIX and was removed in 4.3BSD-Reno. The
setpriority() system calls appeared in 4.1cBSD.
|September 10, 2015||OpenBSD-current|