man3/ctermid.3

   1 .\" Copyright (c) 1993 by Thomas Koenig (ig25@rz.uni-karlsruhe.de)
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  25 .\" Modified Sat Jul 24 19:51:06 1993 by Rik Faith (faith@cs.unc.edu)
  26 .TH CTERMID 3  2019-03-06 "GNU" "Linux Programmer's Manual"
  27 .SH NAME
  28 ctermid \- get controlling terminal name
  29 .SH SYNOPSIS
  30 .nf
  31 .B #include <stdio.h>
  32 .\" POSIX also requires this function to be declared in <unistd.h>,
  33 .\" and glibc does so if suitable feature test macros are defined.
  34 .PP
  35 .BI "char *ctermid(char *" "s" );
  36 .fi
  37 .PP
  38 .in -4n
  39 Feature Test Macro Requirements for glibc (see
  40 .BR feature_test_macros (7)):
  41 .in
  42 .PP
  43 .BR ctermid ():
  44 _POSIX_C_SOURCE
  45 .SH DESCRIPTION
  46 .BR ctermid ()
  47 returns a string which is the pathname for the current
  48 controlling terminal for this process.
  49 If
  50 .I s
  51 is NULL,
  52 a static buffer is used, otherwise
  53 .I s
  54 points to a buffer used to hold the terminal pathname.
  55 The symbolic constant
  56 .B L_ctermid
  57 is the maximum number of characters in the returned pathname.
  58 .SH RETURN VALUE
  59 The pointer to the pathname.
  60 .SH ATTRIBUTES
  61 For an explanation of the terms used in this section, see
  62 .BR attributes (7).
  63 .TS
  64 allbox;
  65 lb lb lb
  66 l l l.
  67 Interface       Attribute       Value
  68 T{
  69 .BR ctermid ()
  70 T}      Thread safety   MT-Safe
  71 .TE
  72 .SH CONFORMING TO
  73 POSIX.1-2001, POSIX.1-2008, Svr4.
  74 .SH BUGS
  75 The returned pathname may not uniquely identify the controlling
  76 terminal; it may, for example, be
  77 .IR /dev/tty .
  78 .PP
  79 It is not assured that the program can open the terminal.
  80 .\" in glibc 2.3.x, x >= 4, the glibc headers threw an error
  81 .\" if ctermid() was given an argument; fixed in 2.4.
  82 .SH SEE ALSO
  83 .BR ttyname (3)