man3/ptsname.3

   1 .\" %%%LICENSE_START(PUBLIC_DOMAIN)
   2 .\" This page is in the public domain. - aeb
   3 .\" %%%LICENSE_END
   4 .\"
   5 .\" 2004-12-17, mtk, added description of ptsname_r() + ERRORS
   6 .\"
   7 .TH PTSNAME 3 2013-06-21 "" "Linux Programmer's Manual"
   8 .SH NAME
   9 ptsname, ptsname_r \- get the name of the slave pseudoterminal
  10 .SH SYNOPSIS
  11 .nf
  12 .BR "#define _XOPEN_SOURCE" "       /* See feature_test_macros(7) */"
  13 .br
  14 .B #include <stdlib.h>
  15 .sp
  16 .BI "char *ptsname(int " fd ");"
  17 .sp
  18 .BR "#define _GNU_SOURCE" "         /* See feature_test_macros(7) */"
  19 .br
  20 .B #include <stdlib.h>
  21 .sp
  22 .BI "int ptsname_r(int " fd ", char *" buf ", size_t " buflen ");"
  23 .fi
  24 .SH DESCRIPTION
  25 The
  26 .BR ptsname ()
  27 function returns the name of the slave pseudoterminal device
  28 corresponding to the master referred to by
  29 .IR fd .
  30
  31 The
  32 .BR ptsname_r ()
  33 function is the reentrant equivalent of
  34 .BR ptsname ().
  35 It returns the name of the slave pseudoterminal device as a
  36 null-terminated string in the buffer pointed to by
  37 .IR buf .
  38 The
  39 .I buflen
  40 argument specifies the number of bytes available in
  41 .IR buf .
  42 .SH RETURN VALUE
  43 On success,
  44 .BR ptsname ()
  45 returns a pointer to a string in static storage which will be
  46 overwritten by subsequent calls.
  47 This pointer must not be freed.
  48 On failure, NULL is returned.
  49
  50 On success,
  51 .BR ptsname_r ()
  52 returns 0.
  53 On failure, a nonzero value is returned
  54 and
  55 .I errno
  56 is set to indicate the error.
  57 .\" In fact the errno value is also returned as the function
  58 .\" result -- MTK, Dec 04
  59 .SH ERRORS
  60 .TP
  61 .B EINVAL
  62 .RB ( ptsname_r ()
  63 only)
  64 .I buf
  65 is NULL.
  66 .TP
  67 .B ENOTTY
  68 .I fd
  69 does not refer to a pseudoterminal master device.
  70 .TP
  71 .B ERANGE
  72 .RB ( ptsname_r ()
  73 only)
  74 .I buf
  75 is too small.
  76 .SH VERSIONS
  77 .BR ptsname ()
  78 is provided in glibc since version 2.1.
  79 .SH ATTRIBUTES
  80 For an explanation of the terms used in this section, see
  81 .BR attributes (7).
  82 .TS
  83 allbox;
  84 lb lb lb
  85 l l l.
  86 Interface       Attribute       Value
  87 T{
  88 .BR ptsname ()
  89 T}      Thread safety   MT-Unsafe
  90 T{
  91 .BR ptsname_r ()
  92 T}      Thread safety   MT-Safe
  93 .TE
  94 .SH CONFORMING TO
  95 .BR ptsname ()
  96 is part of the UNIX 98 pseudoterminal support (see
  97 .BR pts (4)).
  98 This function is specified in POSIX.1-2001.
  99
 100 .BR ptsname_r ()
 101 is a Linux extension.
 102 A version of this function is documented on Tru64 and HP-UX, but
 103 on those implementations, \-1 is returned on error, with
 104 .I errno
 105 set to indicate the error.
 106 Avoid using this function in portable programs.
 107 .SH SEE ALSO
 108 .BR grantpt (3),
 109 .BR posix_openpt (3),
 110 .BR ttyname (3),
 111 .BR unlockpt (3),
 112 .BR pts (4),
 113 .BR pty (7)