man3/ctermid.3

   1 .\" Copyright (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de)
   2 .\"
   3 .\" SPDX-License-Identifier: Linux-man-pages-copyleft
   4 .\"
   5 .\" Modified Sat Jul 24 19:51:06 1993 by Rik Faith (faith@cs.unc.edu)
   6 .TH ctermid 3 (date) "Linux man-pages (unreleased)"
   7 .SH NAME
   8 ctermid \- get controlling terminal name
   9 .SH LIBRARY
  10 Standard C library
  11 .RI ( libc ", " \-lc )
  12 .SH SYNOPSIS
  13 .nf
  14 .B #include <stdio.h>
  15 .\" POSIX also requires this function to be declared in <unistd.h>,
  16 .\" and glibc does so if suitable feature test macros are defined.
  17 .PP
  18 .BI "char *ctermid(char *" "s" );
  19 .fi
  20 .PP
  21 .RS -4
  22 Feature Test Macro Requirements for glibc (see
  23 .BR feature_test_macros (7)):
  24 .RE
  25 .PP
  26 .BR ctermid ():
  27 .nf
  28     _POSIX_C_SOURCE
  29 .fi
  30 .SH DESCRIPTION
  31 .BR ctermid ()
  32 returns a string which is the pathname for the current
  33 controlling terminal for this process.
  34 If
  35 .I s
  36 is NULL,
  37 a static buffer is used, otherwise
  38 .I s
  39 points to a buffer used to hold the terminal pathname.
  40 The symbolic constant
  41 .B L_ctermid
  42 is the maximum number of characters in the returned pathname.
  43 .SH RETURN VALUE
  44 The pointer to the pathname.
  45 .SH ATTRIBUTES
  46 For an explanation of the terms used in this section, see
  47 .BR attributes (7).
  48 .ad l
  49 .nh
  50 .TS
  51 allbox;
  52 lbx lb lb
  53 l l l.
  54 Interface       Attribute       Value
  55 T{
  56 .BR ctermid ()
  57 T}      Thread safety   MT-Safe
  58 .TE
  59 .hy
  60 .ad
  61 .sp 1
  62 .SH STANDARDS
  63 POSIX.1-2001, POSIX.1-2008, Svr4.
  64 .SH BUGS
  65 The returned pathname may not uniquely identify the controlling
  66 terminal; it may, for example, be
  67 .IR /dev/tty .
  68 .PP
  69 It is not assured that the program can open the terminal.
  70 .\" in glibc 2.3.x, x >= 4, the glibc headers threw an error
  71 .\" if ctermid() was given an argument; fixed in 2.4.
  72 .SH SEE ALSO
  73 .BR ttyname (3)