1.\" $OpenBSD: getthrid.2,v 1.4 2016/03/30 06:58:06 jmc Exp $ 2.\" $NetBSD: getpid.2,v 1.5 1995/02/27 12:33:12 cgd Exp $ 3.\" 4.\" Copyright (c) 1980, 1991, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)getpid.2 8.1 (Berkeley) 6/4/93 32.\" 33.Dd $Mdocdate: March 30 2016 $ 34.Dt GETTHRID 2 35.Os 36.Sh NAME 37.Nm getthrid 38.Nd get thread identifier 39.Sh SYNOPSIS 40.In unistd.h 41.Ft pid_t 42.Fn getthrid void 43.Sh DESCRIPTION 44.Fn getthrid 45returns the thread ID of the calling thread. 46This is used in the implementation of the thread library 47.Pq Fl lpthread 48and can appear in the output of system utilities such as 49.Xr ps 1 50and 51.Xr kdump 1 . 52.Pp 53Thread IDs are not a stable interface and should not be used directly 54by applications except for correlation with system utility output. 55Applications should use the 56.Vt pthread_t 57values from 58.Xr pthread_self 3 59and 60.Xr pthread_create 3 61to identify threads within the process itself. 62.Sh RETURN VALUES 63This function is always successful, and no return value is 64reserved to indicate an error. 65.Sh SEE ALSO 66.Xr getpid 2 , 67.Xr __tfork 3 , 68.Xr pthread_create 3 , 69.Xr pthread_self 3 70.Sh STANDARDS 71The 72.Fn getthrid 73syscall is specific to 74.Ox 75and should not be used in portable applications. 76.Sh HISTORY 77The 78.Fn getthrid 79syscall appeared in 80.Ox 3.9 . 81