NAME
pthread_attr_setsched - Changes the scheduling policy attribute of
thread creation
SYNOPSIS
#include <pthread.h>
int pthread_attr_setsched( pthread_attr_t *attr
int *scheduler );
PARAMETERS
attr Thread attributes object modified.
scheduler New value for the scheduling policy attribute.
Valid values are as follows:
SCHED_FIFO (First In, First Out)
The highest-priority thread runs until it
blocks. If there is more than one thread
with the same priority, and that priority
is the highest among other threads, the
first thread to begin running continues
until it blocks.
SCHED_RR (Round Robin)
The highest-priority thread runs until it
blocks; however, threads of equal priority,
if that priority is the highest among other
threads, are timesliced. Timeslicing is a
process in which threads alternate using
available processors.
SCHED_OTHER (Default)
All threads are timesliced. SCHED_OTHER
ensures that all threads, regardless of
priority, receive some scheduling so that
no thread is completely denied execution
time. (However, SCHED_OTHER threads can be
denied execution time by SCHED_FIFO or
SCHED_RR threads.)
SCHED_FG_NP (Foreground)
Same as SCHED_OTHER. Threads are time-
sliced and priorities can be modified
dynamically by the scheduler to ensure
fairness.
SCHED_BG_NP (Background)
Ensures that all threads, regardless of
priority, receive some scheduling. However,
SCHED_BG_NP can be denied execution by
SCHED_FIFO or SCHED_RR threads.
DESCRIPTION
The pthread_attr_setsched() routine sets the scheduling policy of a
thread that is created using the attributes object specified by the attr
parameter. The default value of the scheduling attribute is SCHED_OTHER.
RETURN VALUES
If the function fails, errno may be set to one of the following values:
Return Error Description
___________________________________________________________
0 Successful completion.
-1 [EINVAL] The value specified by attr is invalid.
-1 [EINVAL] The value specified by scheduler is invalid.
-1 [EPERM] The caller does not have the appropriate
privileges to set the priority of the
specified thread.
RELATED INFORMATION
FUNCTIONS: pthread_attr_create
pthread_attr_getsched
pthread_attr_setinheritsched
pthread_create