gen/FreeBSD/ctermid.3

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  28 .\"     @(#)ctermid.3   8.1 (Berkeley) 6/4/93
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  31 .Dd October 1, 2011
  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 *buf"
  44 .Ft char *
  45 .Fn ctermid_r "char *buf"
  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 buf
  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 buf .
  59 The argument
  60 .Fa buf
  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 buf
  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 The
  85 .Fn ctermid
  86 function returns
  87 .Fa buf
  88 if it is
  89 .Pf non- Dv NULL ,
  90 otherwise it returns the address of a static buffer.
  91 The
  92 .Fn ctermid_r
  93 function always returns
  94 .Fa buf ,
  95 even if it is the NULL pointer.
  96 .Sh ERRORS
  97 The current implementation detects no error conditions.
  98 .Sh SEE ALSO
  99 .Xr ttyname 3
 100 .Sh STANDARDS
 101 The
 102 .Fn ctermid
 103 function conforms to
 104 .St -p1003.1-88 .
 105 .Sh BUGS
 106 By default the
 107 .Fn ctermid
 108 function
 109 writes all information to an internal static object.
 110 Subsequent calls to
 111 .Fn ctermid
 112 will modify the same object.