pthread_attr_getschedpolicy, pthread_attr_setschedpolicy Subroutine

Purpose

Gets and sets the schedpolicy attribute (REALTIME THREADS).

Syntax

#include <pthread.h>
#include <time.h>

int pthread_attr_getschedpolicy(const pthread_attr_t *restrict attr,
       int *restrict policy);
int pthread_attr_setschedpolicy(pthread_attr_t *attr, int policy);

Description

The pthread_attr_getschedpolicy() and pthread_attr_setschedpolicy() functions, respectively, get and set the schedpolicy attribute in the attr argument.

The supported values of policy include SCHED_FIFO, SCHED_RR, and SCHED_OTHER, which are defined in the <sched.h> header. When threads executing with the scheduling policy SCHED_FIFO, SCHED_RR, or SCHED_SPORADIC are waiting on a mutex, they acquire the mutex in priority order when the mutex is unlocked.

Application Usage

After these attributes have been set, a thread can be created with the specified attributes using pthread_create(). Using these routines does not affect the current running thread.

Return Values

If successful, the pthread_attr_getschedpolicy() and pthread_attr_setschedpolicy() functions return 0; otherwise, an error number is returned to indicate the error.

Error Codes

The pthread_attr_setschedpolicy() function might fail if:

These functions do not return an error code of EINTR.