.\" Copyright (c) 2008 David Xu <davidxu@FreeBSD.org>
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.\" $FreeBSD: head/lib/libc/gen/tcgetsid.3 208291 2010-05-19 08:57:53Z uqs $
.\"
.Dd April 15, 2008
.Dt TCGETSID 3
.Os
.Sh NAME
.Nm tcgetsid
.Nd get session ID associated with a controlling terminal
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/types.h
.In termios.h
.Ft pid_t
.Fn tcgetsid "int fd"
.Sh DESCRIPTION
The
.Fn tcgetsid
function returns the process group ID of the session leader for a
controlling terminal specified by
.Fa fd .
.Sh ERRORS
If an error occurs,
.Fn tcgetsid
returns -1 and the global variable
.Va errno
is set to indicate the error, as follows:
.Bl -tag -width Er
.It Bq Er EBADF
The
.Fa fd
argument is not a valid file descriptor.
.It Bq Er ENOTTY
The calling process does not have a controlling terminal or the
underlying terminal device represented by
.Fa fd
is not the controlling terminal.
.El
.Sh SEE ALSO
.Xr getsid 2 ,
.Xr setsid 2 ,
.Xr tcgetpgrp 3 ,
.Xr tcsetsid 3
.Sh STANDARDS
The
.Fn tcgetsid
function conforms to
.St -xpg4.2 .