.\"	$OpenBSD: getthrid.2,v 1.3 2015/05/31 23:54:25 schwarze Exp $
.\"	$NetBSD: getpid.2,v 1.5 1995/02/27 12:33:12 cgd Exp $
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.\"     @(#)getpid.2	8.1 (Berkeley) 6/4/93
.\"
.Dd $Mdocdate: May 31 2015 $
.Dt GETTHRID 2
.Os
.Sh NAME
.Nm getthrid
.Nd get thread identifier
.Sh SYNOPSIS
.In unistd.h
.Ft pid_t
.Fn getthrid void
.Sh DESCRIPTION
.Fn getthrid
returns the thread ID of the calling thread.
This is used in the implementation of the thread library
.Pq Fl lpthread
and can appear in the output of system utilities such as
.Xr ps 1
and
.Xr kdump 1 .
.Pp
Thread IDs are not a stable interface and should not be used directly
by applications except for correlation with system utility output.
Applications should use the
.Vt pthread_t
values from
.Xr pthread_self 3
and
.Xr pthread_create 3
to identify threads within the process itself.
.Sh RETURN VALUES
This function is always successful, and no return value is
reserved to indicate an error.
.Sh SEE ALSO
.Xr __tfork 2 ,
.Xr getpid 2 ,
.Xr pthread_create 3 ,
.Xr pthread_self 3
.Sh STANDARDS
The
.Fn getthrid
syscall is specific to
.Ox
and should not be used in portable applications.
.Sh HISTORY
The
.Fn getthrid
syscall appeared in
.Ox 3.9 .