freebsd-skq/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.
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.\" This documentation was written by
.\" Konstantin Belousov <kib@FreeBSD.org> under sponsorship
.\" from the FreeBSD Foundation.
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.\" $FreeBSD$
.\"
.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.