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