table of contents
|GETPRIORITY(2)||System Calls Manual||GETPRIORITY(2)|
LIBRARY¶Standard C Library (libc, -lc)
which, int who,
DESCRIPTION¶The scheduling priority of the process, process group, or user, as indicated by which and who is obtained with the
getpriority() system call and set with the
setpriority() system call. The which argument 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. The prio argument is a value in the range -20 to 20. The default priority is 0; lower priorities cause more favorable scheduling.
getpriority() system call returns the
highest priority (lowest numerical value) enjoyed by any of the specified
setpriority() system call sets the
priorities of all of the specified processes to the specified value. Only
the super-user 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.
setpriority() function returns the value 0
if successful; otherwise the value -1 is returned and the global
variable errno is set to indicate the error.
setpriority() system calls will fail if:
- No process was located using the which and who values specified.
- The which argument was not one of
In addition to the errors indicated above,
setpriority() will fail if:
SEE ALSO¶nice(1), fork(2), renice(8)
getpriority() system call appeared in 4.2BSD.
|June 4, 1993||Linux 4.9.0-9-amd64|