+++ /dev/null
-.\" Copyright (C) 2004 Andries Brouwer (aeb@cwi.nl)
-.\"
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-.\" manual provided the copyright notice and this permission notice are
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-.\"
-.\" Permission is granted to copy and distribute modified versions of this
-.\" manual under the conditions for verbatim copying, provided that the
-.\" entire resulting derived work is distributed under the terms of a
-.\" permission notice identical to this one.
-.\"
-.\" Since the Linux kernel and libraries are constantly changing, this
-.\" manual page may be incorrect or out-of-date. The author(s) assume no
-.\" responsibility for errors or omissions, or for damages resulting from
-.\" the use of the information contained herein. The author(s) may not
-.\" have taken the same level of care in the production of this manual,
-.\" which is licensed free of charge, as they might when working
-.\" professionally.
-.\"
-.\" Formatted or processed versions of this manual, if unaccompanied by
-.\" the source, must acknowledge the copyright and authors of this work.
-.\" %%%LICENSE_END
-.\"
-.TH SET_TID_ADDRESS 2 2014-07-08 "Linux" "Linux Programmer's Manual"
-.SH NAME
-set_tid_address \- set pointer to thread ID
-.SH SYNOPSIS
-.nf
-.B #include <linux/unistd.h>
-.sp
-.BI "long set_tid_address(int *" tidptr );
-.fi
-.SH DESCRIPTION
-For each thread, the kernel maintains two attributes (addresses) called
-.I set_child_tid
-and
-.IR clear_child_tid .
-These two attributes contain the value NULL by default.
-.TP
-.I set_child_tid
-If a thread is started using
-.BR clone (2)
-with the
-.B CLONE_CHILD_SETTID
-flag,
-.I set_child_tid
-is set to the value passed in the
-.I ctid
-argument of that system call.
-.IP
-When
-.I set_child_tid
-is set, the very first thing the new thread does
-is to write its thread ID at this address.
-.TP
-.I clear_child_tid
-If a thread is started using
-.BR clone (2)
-with the
-.B CLONE_CHILD_CLEARTID
-flag,
-.I clear_child_tid
-is set to the value passed in the
-.I ctid
-argument of that system call.
-.LP
-The system call
-.BR set_tid_address ()
-sets the
-.I clear_child_tid
-value for the calling thread to
-.IR tidptr .
-.LP
-When a thread whose
-.I clear_child_tid
-is not NULL terminates, then,
-if the thread is sharing memory with other threads,
-then 0 is written at the address specified in
-.I clear_child_tid
-and the kernel performs the following operation:
-
- futex(clear_child_tid, FUTEX_WAKE, 1, NULL, NULL, 0);
-
-The effect of this operation is to wake a single thread that
-is performing a futex wait on the memory location.
-Errors from the futex wake operation are ignored.
-.SH RETURN VALUE
-.BR set_tid_address ()
-always returns the caller's thread ID.
-.SH ERRORS
-.BR set_tid_address ()
-always succeeds.
-.SH VERSIONS
-This call is present since Linux 2.5.48.
-Details as given here are valid since Linux 2.5.49.
-.SH CONFORMING TO
-This system call is Linux-specific.
-.SH SEE ALSO
-.BR clone (2),
-.BR futex (2),
-.BR gettid (2)
-.SH COLOPHON
-This page is part of release 3.79 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
-\%http://www.kernel.org/doc/man\-pages/.
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