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.TH PTHREAD_ATTR_SETSCHEDPOLICY 3 2021-03-22 "Linux" "Linux Programmer's Manual"
.SH NAME
pthread_attr_setschedpolicy, pthread_attr_getschedpolicy \- set/get
scheduling policy attribute in thread attributes object
.SH SYNOPSIS
.nf
.B #include <pthread.h>
.PP
.BI "int pthread_attr_setschedpolicy(pthread_attr_t *" attr ", int " policy );
.BI "int pthread_attr_getschedpolicy(const pthread_attr_t *restrict " attr ,
.BI "                                int *restrict " policy );
.PP
Compile and link with \fI\-pthread\fP.
.fi
.SH DESCRIPTION
The
.BR pthread_attr_setschedpolicy ()
function sets the scheduling policy attribute of the
thread attributes object referred to by
.IR attr
to the value specified in
.IR policy .
This attribute determines the scheduling policy of
a thread created using the thread attributes object
.IR attr .
.PP
The supported values for
.I policy
are
.BR SCHED_FIFO ,
.BR SCHED_RR ,
and
.BR SCHED_OTHER ,
with the semantics described in
.BR sched (7).
.\" FIXME . pthread_setschedparam() places no restriction on the policy,
.\" but pthread_attr_setschedpolicy() restricts policy to RR/FIFO/OTHER
.\" http://sourceware.org/bugzilla/show_bug.cgi?id=7013
.PP
The
.BR pthread_attr_getschedpolicy ()
returns the scheduling policy attribute of the thread attributes object
.IR attr
in the buffer pointed to by
.IR policy .
.PP
In order for the policy setting made by
.BR pthread_attr_setschedpolicy ()
to have effect when calling
.BR pthread_create (3),
the caller must use
.BR pthread_attr_setinheritsched (3)
to set the inherit-scheduler attribute of the attributes object
.I attr
to
.BR PTHREAD_EXPLICIT_SCHED .
.SH RETURN VALUE
On success, these functions return 0;
on error, they return a nonzero error number.
.SH ERRORS
.BR pthread_attr_setschedpolicy ()
can fail with the following error:
.TP
.B EINVAL
Invalid value in
.IR policy .
.PP
POSIX.1 also documents an optional
.B ENOTSUP
error ("attempt was made to set the attribute to an unsupported value") for
.BR pthread_attr_setschedpolicy ().
.\" .SH VERSIONS
.\" Available since glibc 2.0.
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.ad l
.nh
.TS
allbox;
lbx lb lb
l l l.
Interface	Attribute	Value
T{
.BR pthread_attr_setschedpolicy (),
.BR pthread_attr_getschedpolicy ()
T}	Thread safety	MT-Safe
.TE
.hy
.ad
.sp 1
.SH CONFORMING TO
POSIX.1-2001, POSIX.1-2008.
.SH EXAMPLES
See
.BR pthread_setschedparam (3).
.SH SEE ALSO
.ad l
.nh
.BR pthread_attr_init (3),
.BR pthread_attr_setinheritsched (3),
.BR pthread_attr_setschedparam (3),
.BR pthread_create (3),
.BR pthread_setschedparam (3),
.BR pthread_setschedprio (3),
.BR pthreads (7),
.BR sched (7)