freebsd-nq/lib/libc/sys/thr_exit.2
Jilles Tjoelker 9de9fa32c9 thr_*(2): Add xrefs to what libthr implements using each syscall.
Add text to thr_exit(2) and thr_new(2) discouraging their use in
applications since calling these in a process with libthr loaded will
confuse libthr and is likely to cause hangs or crashes.

The thr_kill2(2) call is not used by libthr and may be useful in special
applications.

The other calls can be used in applications but it should not be necessary.
2016-06-01 21:58:13 +00:00

91 lines
2.7 KiB
Groff

.\" Copyright (c) 2016 The FreeBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This documentation was written by
.\" Konstantin Belousov <kib@FreeBSD.org> under sponsorship
.\" from the FreeBSD Foundation.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd June 1, 2016
.Dt THR_EXIT 2
.Os
.Sh NAME
.Nm thr_exit
.Nd terminate current thread
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/thr.h
.Ft void
.Fn thr_exit "long *state"
.Sh DESCRIPTION
.Bf -symbolic
This function is intended for implementing threading.
Normal applications should call
.Xr pthread_exit 3
instead.
.Ef
.Pp
The
.Fn thr_exit
system call terminates the current kernel-scheduled thread.
.Pp
If the
.Fa state
argument is not
.Dv NULL ,
the location pointed to by the argument is
updated with an arbitrary non-zero value, and an
.Xr _umtx_op 2
.Dv UMTX_OP_WAKE
operation is consequently performed on the location.
.Pp
Attempts to terminate the last thread in the process are silently ignored.
Use
.Xr _exit 2
syscall to terminate the process.
.Sh RETURN VALUES
The function does not return a value.
A return from the function indicates that the calling thread was the
last one in the process.
.Sh SEE ALSO
.Xr _exit 2 ,
.Xr thr_kill 2 ,
.Xr thr_kill2 2 ,
.Xr thr_new 2 ,
.Xr thr_self 2 ,
.Xr thr_set_name 2 ,
.Xr _umtx_op 2 ,
.Xr pthread_exit 3
.Sh STANDARDS
The
.Fn thr_exit
system call is non-standard and is used by
.Lb libthr
to implement
.St -p1003.1-2001
.Xr pthread 3
functionality.