pthread_getschedparam Subroutine

Purpose

Returns the current schedpolicy and schedparam attributes of a thread.

Library

Threads Library (libpthreads.a)

Syntax

#include <pthread.h>
#include <sys/sched.h>

int pthread_getschedparam ( thread, schedpolicy, schedparam) pthread_t thread; int *schedpolicy; struct sched_param *schedparam;

Description

The pthread_getschedparam subroutine returns the current schedpolicy and schedparam attributes of the thread thread. The schedpolicy attribute specifies the scheduling policy of a thread. It may have one of the following values:

Item	Description
SCHED_FIFO	Denotes first-in first-out scheduling.
SCHED_RR	Denotes round-robin scheduling.
SCHED_OTHER	Denotes the default operating system scheduling policy. It is the default value.

The schedparam attribute specifies the scheduling parameters of a thread created with this attributes object. The sched_priority field of the sched_param structure contains the priority of the thread. It is an integer value.

Note: The pthread.h header file must be the first included file of each source file using the threads library. Otherwise, the -D_THREAD_SAFE compilation flag should be used, or the cc_r compiler used. In this case, the flag is automatically set.

The implementation of this subroutine is dependent on the priority scheduling POSIX option. The priority scheduling POSIX option is implemented in the operating system.

Parameters

Item	Description
thread	Specifies the target thread.
schedpolicy	Points to where the schedpolicy attribute value will be stored.
schedparam	Points to where the schedparam attribute value will be stored.

Return Values

Upon successful completion, the current value of the schedpolicy and schedparam attributes are returned via the schedpolicy and schedparam parameters, and 0 is returned. Otherwise, an error code is returned.

Error Codes

The pthread_getschedparam subroutine is unsuccessful if the following is true:

Item	Description
ESRCH	The thread thread does not exist.