gen/FreeBSD/ctermid.3

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  28 .\"     @(#)ctermid.3   8.1 (Berkeley) 6/4/93
  29 .\" $FreeBSD: src/lib/libc/gen/ctermid.3,v 1.12 2007/01/09 00:27:53 imp Exp $
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  31 .Dd June 4, 1993
  32 .Dt CTERMID 3
  33 .Os
  34 .Sh NAME
  35 .Nm ctermid
  36 .Nd generate terminal pathname
  37 .Sh LIBRARY
  38 .Lb libc
  39 .Sh SYNOPSIS
  40 .In stdio.h
  41 .Ft char *
  42 .Fn ctermid "char *buf"
  43 .Ft char *
  44 .Fn ctermid_r "char *buf"
  45 .Sh DESCRIPTION
  46 The
  47 .Fn ctermid
  48 function generates a string, that, when used as a pathname, refers to
  49 the current controlling terminal of the calling process.
  50 .Pp
  51 If
  52 .Fa buf
  53 is the
  54 .Dv NULL
  55 pointer, a pointer to a static area is returned.
  56 Otherwise, the pathname is copied into the memory referenced by
  57 .Fa buf .
  58 The argument
  59 .Fa buf
  60 is assumed to be at least
  61 .Dv L_ctermid
  62 (as defined in the include
  63 file
  64 .In stdio.h )
  65 bytes long.
  66 .Pp
  67 The
  68 .Fn ctermid_r
  69 function
  70 provides the same functionality as
  71 .Fn ctermid
  72 except that if
  73 .Fa buf
  74 is a
  75 .Dv NULL
  76 pointer,
  77 .Dv NULL
  78 is returned.
  79 .Pp
  80 The current implementation simply returns
  81 .Ql /dev/tty .
  82 .Sh RETURN VALUES
  83 Upon successful completion, a
  84 .Pf non- Dv NULL
  85 pointer is returned.
  86 Otherwise, a
  87 .Dv NULL
  88 pointer is returned and the global variable
  89 .Va errno
  90 is set to indicate the error.
  91 .Sh ERRORS
  92 The current implementation detects no error conditions.
  93 .Sh SEE ALSO
  94 .Xr ttyname 3
  95 .Sh STANDARDS
  96 The
  97 .Fn ctermid
  98 function conforms to
  99 .St -p1003.1-88 .
 100 .Sh BUGS
 101 By default the
 102 .Fn ctermid
 103 function
 104 writes all information to an internal static object.
 105 Subsequent calls to
 106 .Fn ctermid
 107 will modify the same object.