gen/FreeBSD/ctermid.3

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  32 .\"     @(#)ctermid.3   8.1 (Berkeley) 6/4/93
  33 .\" $FreeBSD: src/lib/libc/gen/ctermid.3,v 1.11 2003/09/08 19:57:14 ru Exp $
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  35 .Dd June 4, 1993
  36 .Dt CTERMID 3
  37 .Os
  38 .Sh NAME
  39 .Nm ctermid
  40 .Nd generate terminal pathname
  41 .Sh LIBRARY
  42 .Lb libc
  43 .Sh SYNOPSIS
  44 .In stdio.h
  45 .Ft char *
  46 .Fn ctermid "char *buf"
  47 .Ft char *
  48 .Fn ctermid_r "char *buf"
  49 .Sh DESCRIPTION
  50 The
  51 .Fn ctermid
  52 function generates a string, that, when used as a pathname, refers to
  53 the current controlling terminal of the calling process.
  54 .Pp
  55 If
  56 .Fa buf
  57 is the
  58 .Dv NULL
  59 pointer, a pointer to a static area is returned.
  60 Otherwise, the pathname is copied into the memory referenced by
  61 .Fa buf .
  62 The argument
  63 .Fa buf
  64 is assumed to be at least
  65 .Dv L_ctermid
  66 (as defined in the include
  67 file
  68 .In stdio.h )
  69 bytes long.
  70 .Pp
  71 The
  72 .Fn ctermid_r
  73 function
  74 provides the same functionality as
  75 .Fn ctermid
  76 except that if
  77 .Fa buf
  78 is a
  79 .Dv NULL
  80 pointer,
  81 .Dv NULL
  82 is returned.
  83 .Pp
  84 The current implementation simply returns
  85 .Ql /dev/tty .
  86 .Sh RETURN VALUES
  87 Upon successful completion, a
  88 .Pf non- Dv NULL
  89 pointer is returned.
  90 Otherwise, a
  91 .Dv NULL
  92 pointer is returned and the global variable
  93 .Va errno
  94 is set to indicate the error.
  95 .Sh ERRORS
  96 The current implementation detects no error conditions.
  97 .Sh SEE ALSO
  98 .Xr ttyname 3
  99 .Sh STANDARDS
 100 The
 101 .Fn ctermid
 102 function conforms to
 103 .St -p1003.1-88 .
 104 .Sh BUGS
 105 By default the
 106 .Fn ctermid
 107 function
 108 writes all information to an internal static object.
 109 Subsequent calls to
 110 .Fn ctermid
 111 will modify the same object.