PTHREAD_ATTR_GETSCHEDPOLICY(3P)

PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

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

SYNOPSIS

#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, or SCHED_SPORADIC are waiting on a mutex, they shall acquire the mutex in priority order when the mutex is unlocked.

The behavior is undefined if the value specified by the attr argument to pthread_attr_getschedpolicy() or pthread_attr_setschedpolicy() does not refer to an initialized thread attributes object.

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 shall fail if:

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

The pthread_attr_setschedpolicy() function may fail if:

EINVAL
    The value of policy is not valid.

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(). Using these routines does not affect the current running thread.

See Section 2.9.4, Thread Scheduling for further details on thread scheduling attributes and their default settings.

RATIONALE
If an implementation detects that the value specified by the attr argument to pthread_attr_getschedpolicy() or pthread_attr_setschedpolicy() does not refer to an initialized thread attributes object, it is recommended that the function should fail and report an [EINVAL] error.

FUTURE DIRECTIONS
None.

SEE ALSO
pthread_attr_destroy(), pthread_attr_getscope(), pthread_attr_getinheritsched(), pthread_attr_getschedparam(), pthread_create()

The Base Definitions volume of POSIX.1-2017, <pthread.h>, <sched.h>

COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .