Name

pthread_setscheduler − Changes the current scheduling policy and priority of a thread. 

Syntax

#include <pthread.h>

int pthread_setscheduler (thread, scheduler, priority)
pthread_t thread;
int scheduler;
int priority;

Arguments

thread Thread whose scheduling policy is to be changed. 

scheduler
New scheduling policy value for the thread specified in thread.  (Policies listed on the same line are equivalent.) Valid values are as follows:

SCHED_FIFO

SCHED_RR

SCHED_FG_NP or SCHED_OTHER

SCHED_BG_NP

priority New priority value of the thread specified in thread. The priority attribute is dependent upon scheduling policy.  Valid values fall within one of the following three ranges. 

If you create a new thread without specifying a threads attributes object that contains a changed priority attribute, the default priority of the newly created thread is the midpoint between PRI_OTHER_MIN and PRI_OTHER_MAX (the midpoint between the minimum and the maximum for the SCHED_OTHER policy). 

Description

This routine changes the current scheduling policy and priority of a thread. Call this routine to change both the priority and scheduling policy of a thread at the same time.  To change only the priority, call the pthread_setprio routine. 

A thread changes its own scheduling policy and priority by using the identifier returned by pthread_self.  Changing the scheduling policy or priority, or both, of a thread can cause it to start executing or to be preempted by another thread. 

This routine is different from pthread_attr_setprio and pthread_attr_setsched because those routines set the priority and scheduling policy attributes that are used to establish the priority and scheduling policy of a new thread when it is created.  This routine, however, changes the priority and scheduling policy of an existing thread. 

Return Values

If an error condition occurs, this routine returns -1 and sets errno to the corresponding error value.  Possible return values are as follows.