PTHREAD_GETSCHEDPARAM(3C) Standard C Library Functions

NAME

pthread_getschedparam, pthread_setschedparam - access dynamic thread
scheduling parameters

SYNOPSIS

cc -mt [ flag... ] file... -lpthread [ library... ]
#include <pthread.h>

int pthread_getschedparam(pthread_t thread, int *restrict policy,
struct sched_param *restrict param);


int pthread_setschedparam(pthread_t thread, int policy,
const struct sched_param *param);

DESCRIPTION

The pthread_getschedparam() and pthread_setschedparam() functions
allow the scheduling policy and scheduling parameters of individual
threads within a multithreaded process to be retrieved and set.
Supported policies are :

SCHED_OTHER
traditional time-sharing scheduling class


SCHED_FIFO
real-time class: run to completion


SCHED_RR
real-time class: round-robin


SCHED_IA
interactive time-sharing class


SCHED_FSS
fair-share scheduling class


SCHED_FX
fixed priority scheduling class


See pthreads(7). The affected scheduling parameter is the
sched_priority member of the sched_param structure.


The pthread_getschedparam() function retrieves the scheduling policy
and scheduling parameters for the thread whose thread ID is given by
thread and stores those values in policy and param, respectively. The
priority value returned from pthread_getschedparam() is the value
specified by the most recent pthread_setschedparam() or
pthread_create() call affecting the target thread, and does not
reflect any temporary adjustments to its priority as a result of any
priority inheritance or ceiling functions. The
pthread_setschedparam() function sets the scheduling policy and
associated scheduling parameters for the thread whose thread ID is
given by thread to the policy and associated parameters provided in
policy and param, respectively.


If the pthread_setschedparam() function fails, no scheduling
parameters will be changed for the target thread.

RETURN VALUES

If successful, the pthread_getschedparam() and
pthread_setschedparam() functions return 0. Otherwise, an error
number is returned to indicate the error.

ERRORS

The pthread_getschedparam() and pthread_setschedparam() functions
will fail if:

ESRCH
The value specified by thread does not refer to an existing
thread.


The pthread_setschedparam() function will fail if:

EINVAL
The value specified by policy or one of the scheduling
parameters associated with the scheduling policy policy is
invalid.


EPERM
The caller does not have the appropriate permission to set
either the scheduling parameters or the scheduling policy
of the specified thread.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------+
|Interface Stability | Committed |
+--------------------+-------------------+
|MT-Level | MT-Safe |
+--------------------+-------------------+
|Standard | See standards(7). |
+--------------------+-------------------+

SEE ALSO

pthread_attr_init(3C), sched_get_priority_max(3C),
sched_get_priority_min(3C), sched_getparam(3C),
sched_getscheduler(3C), sched_setparam(3C), sched_setscheduler(3C),
attributes(7), pthreads(7), standards(7)

February 21, 2023 PTHREAD_GETSCHEDPARAM(3C)