GETPRIORITY
Section: System Calls (2)
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BSD mandoc
BSD 4
NAME
getpriority
setpriority
- get/set program scheduling priority
SYNOPSIS
Fd #include <sys/time.h>
Fd #include <sys/resource.h>
Ft int
Fn getpriority int which int who
Ft int
Fn setpriority int which int who int prio
DESCRIPTION
The scheduling
priority of the process, process group, or user, as indicated by
Fa which
and
Fa who
is obtained with the
Fn getpriority
call and set with the
Fn setpriority
call.
Fa Which
is one of
PRIO_PROCESS
PRIO_PGRP
or
PRIO_USER
and
Fa who
is interpreted relative to
Fa which
(a process identifier for
PRIO_PROCESS
process group
identifier for
PRIO_PGRP
and a user ID for
PRIO_USER )
A zero value of
Fa who
denotes the current process, process group, or user.
Fa Prio
is a value in the range -20 to 20. The default priority is 0;
lower priorities cause more favorable scheduling.
The
Fn getpriority
call returns the highest priority (lowest numerical value)
enjoyed by any of the specified processes. The
Fn setpriority
call sets the priorities of all of the specified processes
to the specified value. Only the super-user may lower priorities.
RETURN VALUES
Since
Fn 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
Fn setpriority
call returns 0 if there is no error, or
-1 if there is.
ERRORS
Fn Getpriority
and
Fn setpriority
will fail if:
- Bq Er ESRCH
-
No process was located using the
Fa which
and
Fa who
values specified.
- Bq Er EINVAL
-
Fa Which
was not one of
PRIO_PROCESS
PRIO_PGRP
or
PRIO_USER
In addition to the errors indicated above,
Fn setpriority
will fail if:
- Bq Er EPERM
-
A process was located, but neither its effective nor real user
ID matched the effective user ID of the caller.
- Bq Er EACCES
-
A non super-user attempted to lower a process priority.
SEE ALSO
nice(1),
fork(2),
renice(8)
HISTORY
The
Fn getpriority
function call appeared in
BSD 4.2
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUES
-
- ERRORS
-
- SEE ALSO
-
- HISTORY
-
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Time: 16:28:59 GMT, April 18, 2022