NAME

pthread_attr_getschedpolicy pthread_attr_setschedpolicy — get and set the schedpolicy attribute (REALTIME THREADS)

SYNOPSIS

[THR TPS]
#include <pthread.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, shall get and set the schedpolicy attribute in the attr argument.

The supported values of policy shall 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, [TSP] or SCHED_SPORADIC are waiting on a mutex, they shall acquire the mutex in priority order when the mutex is unlocked.

RETURN VALUE

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

ERRORS

The pthread_attr_setschedpolicy () function may fail if:

[EINVAL]

The value of policy is not valid.

[ENOTSUP]

An attempt was made to set the attribute to an unsupported value.

These functions shall not return an error code of [EINTR].

The following sections are informative.

EXAMPLES

None.

APPLICATION USAGE

After these attributes have been set, a thread can be created with the specified attributes using pthread_create(3). Using these routines does not affect the current running thread.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

pthread_attr_destroy(3) , pthread_attr_getscope(3) , pthread_attr_getinheritsched(3) , pthread_attr_getschedparam(3) , pthread_create(3) , the Base Definitions volume of IEEE Std 1003.1-2001 (“POSIX.1”), <pthread.h>, <sched.h>

CHANGE HISTORY

First released in Issue 5. Included for alignment with the POSIX Threads Extension.

Marked as part of the Realtime Threads Feature Group.

Issue 6

The pthread_attr_getschedpolicy () and pthread_attr_setschedpolicy () functions are marked as part of the Threads and Thread Execution Scheduling options.

The [ENOSYS] error condition has been removed as stubs need not be provided if an implementation does not support the Thread Execution Scheduling option.

The SCHED_SPORADIC scheduling policy is added for alignment with IEEE Std 1003.1d-1999.

The restrict keyword is added to the pthread_attr_getschedpolicy () prototype for alignment with the ISO/IEC 9899:1999 (“ISO C99”) standard.

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