1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)ttyname.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD$ 34.\" 35.Dd June 4, 1993 36.Dt TTYNAME 3 37.Os 38.Sh NAME 39.Nm ttyname , 40.Nm isatty , 41.Nm ttyslot 42.Nd get name of associated terminal (tty) from file descriptor 43.Sh SYNOPSIS 44.Fd #include <unistd.h> 45.Ft char * 46.Fn ttyname "int fd" 47.Ft int 48.Fn isatty "int fd" 49.Ft int 50.Fn ttyslot void 51.Sh DESCRIPTION 52These functions operate on the system file descriptors for terminal 53type devices. These descriptors are not related to the standard 54.Tn I/O 55.Dv FILE 56typedef, but refer to the special device files found in 57.Pa /dev 58and named 59.Pa /dev/tty Ns Em xx 60and for which an entry exists 61in the initialization file 62.Pa /etc/ttys. 63(See 64.Xr ttys 5 . ) 65.Pp 66The 67.Fn isatty 68function 69determines if the file descriptor 70.Fa fd 71refers to a valid 72terminal type device. 73.Pp 74The 75.Fn ttyname 76function 77gets the related device name of 78a file descriptor for which 79.Fn isatty 80is true 81.Pp 82The 83.Fn ttyslot 84function 85fetches the current process' control terminal number from the 86.Xr ttys 5 87file entry. 88.Sh RETURN VALUES 89The 90.Fn ttyname 91function 92returns the null terminated name if the device is found and 93.Fn isatty 94is true; otherwise 95a 96.Dv NULL 97pointer is returned. 98.Pp 99The 100.Fn ttyslot 101function 102returns the unit number of the device file if found; otherwise 103the value zero is returned. 104.Sh FILES 105.Bl -tag -width /etc/ttys -compact 106.It Pa /dev/\(** 107.It Pa /etc/ttys 108.El 109.Sh SEE ALSO 110.Xr ioctl 2 , 111.Xr ttys 5 112.Sh HISTORY 113A 114.Fn isatty , 115.Fn ttyname , 116and 117.Fn ttyslot 118function 119appeared in 120.At v7 . 121.Sh BUGS 122The 123.Fn ttyname 124function leaves its result in an internal static object and returns 125a pointer to that object. Subsequent calls to 126.Fn ttyname 127will modify the same object. 128