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.TH PTHREAD_ATTR_SETINHERITSCHED 3 2017-09-15 "Linux" "Linux Programmer's Manual"

.SH NAME

pthread_attr_setinheritsched, pthread_attr_getinheritsched \- set/get

inherit-scheduler attribute in thread attributes object

.SH SYNOPSIS

.nf

.B #include <pthread.h>

.PP

.BI "int pthread_attr_setinheritsched(pthread_attr_t *" attr ,

.BI "                                 int " inheritsched );

.BI "int pthread_attr_getinheritsched(const pthread_attr_t *" attr ,

.BI "                                 int *" inheritsched );

.PP

Compile and link with \fI\-pthread\fP.

.fi

.SH DESCRIPTION

The

.BR pthread_attr_setinheritsched ()

function sets the inherit-scheduler attribute of the

thread attributes object referred to by

.IR attr

to the value specified in

.IR inheritsched .

The inherit-scheduler attribute determines whether a thread created using

the thread attributes object

.I attr

will inherit its scheduling attributes from the calling thread

or whether it will take them from

.IR attr .

.PP

The following scheduling attributes are affected by the

inherit-scheduler attribute:

scheduling policy

.RB ( pthread_attr_setschedpolicy (3)),

scheduling priority

.RB ( pthread_attr_setschedparam (3)),

and contention scope

.RB ( pthread_attr_setscope (3)).

.PP

The following values may be specified in

.IR inheritsched :

.TP

.B PTHREAD_INHERIT_SCHED

Threads that are created using

.I attr

inherit scheduling attributes from the creating thread;

the scheduling attributes in

.I attr

are ignored.

.TP

.B PTHREAD_EXPLICIT_SCHED

Threads that are created using

.I attr

take their scheduling attributes from the values specified

by the attributes object.

.\" FIXME Document the defaults for scheduler settings

.PP

The default setting of the inherit-scheduler attribute in

a newly initialized thread attributes object is

.BR PTHREAD_INHERIT_SCHED .

.PP

The

.BR pthread_attr_getinheritsched ()

returns the inherit-scheduler attribute of the thread attributes object

.IR attr

in the buffer pointed to by

.IR inheritsched .

.SH RETURN VALUE

On success, these functions return 0;

on error, they return a nonzero error number.

.SH ERRORS

.BR pthread_attr_setinheritsched ()

can fail with the following error:

.TP

.B EINVAL

Invalid value in

.IR inheritsched .

.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_setinheritsched ().

.\" .SH VERSIONS

.\" Available since glibc 2.0.

.SH ATTRIBUTES

For an explanation of the terms used in this section, see

.BR attributes (7).

.TS

allbox;

lbw31 lb lb

l l l.

Interface	Attribute	Value

T{

.BR pthread_attr_setinheritsched (),

.BR pthread_attr_getinheritsched ()

T}	Thread safety	MT-Safe

.TE

.SH CONFORMING TO

POSIX.1-2001, POSIX.1-2008.

.SH BUGS

As at glibc 2.8, if a thread attributes object is initialized using

.BR pthread_attr_init (3),

then the scheduling policy of the attributes object is set to

.BR SCHED_OTHER

and the scheduling priority is set to 0.

However, if the inherit-scheduler attribute is then set to

.BR PTHREAD_EXPLICIT_SCHED ,

then a thread created using the attribute object

wrongly inherits its scheduling attributes from the creating thread.

This bug does not occur if either the scheduling policy or

scheduling priority attribute is explicitly set

in the thread attributes object before calling

.BR pthread_create (3).

.\" FIXME . Track status of the following bug:

.\" http://sourceware.org/bugzilla/show_bug.cgi?id=7007

.SH EXAMPLE

See

.BR pthread_setschedparam (3).

.SH SEE ALSO

.ad l

.nh

.BR pthread_attr_init (3),

.BR pthread_attr_setschedparam (3),

.BR pthread_attr_setschedpolicy (3),

.BR pthread_attr_setscope (3),

.BR pthread_create (3),

.BR pthread_setschedparam (3),

.BR pthread_setschedprio (3),

.BR pthreads (7),

.BR sched (7)

.SH COLOPHON

This page is part of release 4.15 of the Linux

.I man-pages

project.

A description of the project,

information about reporting bugs,

and the latest version of this page,

can be found at

\%https://www.kernel.org/doc/man\-pages/.