bsd/man/man2/readlink.2

   1 .\"     $NetBSD: readlink.2,v 1.7 1995/02/27 12:35:54 cgd Exp $
   2 .\"
   3 .\" Copyright (c) 1983, 1991, 1993
   4 .\"     The Regents of the University of California.  All rights reserved.
   5 .\"
   6 .\" Redistribution and use in source and binary forms, with or without
   7 .\" modification, are permitted provided that the following conditions
   8 .\" are met:
   9 .\" 1. Redistributions of source code must retain the above copyright
  10 .\"    notice, this list of conditions and the following disclaimer.
  11 .\" 2. Redistributions in binary form must reproduce the above copyright
  12 .\"    notice, this list of conditions and the following disclaimer in the
  13 .\"    documentation and/or other materials provided with the distribution.
  14 .\" 3. All advertising materials mentioning features or use of this software
  15 .\"    must display the following acknowledgement:
  16 .\"     This product includes software developed by the University of
  17 .\"     California, Berkeley and its contributors.
  18 .\" 4. Neither the name of the University nor the names of its contributors
  19 .\"    may be used to endorse or promote products derived from this software
  20 .\"    without specific prior written permission.
  21 .\"
  22 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32 .\" SUCH DAMAGE.
  33 .\"
  34 .\"     @(#)readlink.2  8.1 (Berkeley) 6/4/93
  35 .\"
  36 .Dd June 4, 1993
  37 .Dt READLINK 2
  38 .Os BSD 4.2
  39 .Sh NAME
  40 .Nm readlink
  41 .Nd read value of a symbolic link
  42 .Sh SYNOPSIS
  43 .Fd #include <unistd.h>
  44 .Ft  ssize_t
  45 .Fo readlink
  46 .Fa "const char *restrict path"
  47 .Fa "char *restrict buf"
  48 .Fa "size_t bufsize"
  49 .Fc
  50 .Sh DESCRIPTION
  51 .Fn Readlink
  52 places the contents of the symbolic link
  53 .Fa path
  54 in the buffer
  55 .Fa buf ,
  56 which has size
  57 .Fa bufsize .
  58 .Nm Readlink
  59 does not append a
  60 .Dv NUL
  61 character to
  62 .Fa buf .
  63 .Sh RETURN VALUES
  64 The call returns the count of characters placed in the buffer
  65 if it succeeds, or a -1 if an error occurs, placing the error
  66 code in the global variable
  67 .Va errno .
  68 .Sh ERRORS
  69 .Fn Readlink
  70 will fail if:
  71 .Bl -tag -width Er
  72 .\" ===========
  73 .It Bq Er EACCES
  74 Search permission is denied for a component of the path prefix.
  75 .\" ===========
  76 .It Bq Er EFAULT
  77 .Fa Buf
  78 extends outside the process's allocated address space.
  79 .\" ===========
  80 .It Bq Er EINVAL
  81 The named file is not a symbolic link.
  82 .\" ===========
  83 .It Bq Er EIO
  84 An I/O error occurred while reading from the file system.
  85 .\" ===========
  86 .It Bq Er ELOOP
  87 Too many symbolic links are encountered in translating the pathname.
  88 This is taken to be indicative of a looping symbolic link.
  89 .\" ===========
  90 .It Bq Er ENAMETOOLONG
  91 A component of a pathname exceeded
  92 .Dv {NAME_MAX}
  93 characters, or an entire path name
  94 (possibly expanded by a symbolic link) exceeded
  95 .Dv {PATH_MAX}
  96 characters.
  97 .\" ===========
  98 .It Bq Er ENOENT
  99 The named file does not exist.
 100 .\" ===========
 101 .It Bq Er ENOTDIR
 102 A component of the path prefix is not a directory.
 103 .El
 104 .Sh LEGACY SYNOPSIS
 105 .Fd #include <unistd.h>
 106 .Pp
 107 .Ft int
 108 .br
 109 .Fo readlink
 110 .Fa "const char *path"
 111 .Fa "char *buf"
 112 .Fa "int bufsize"
 113 .Fc ;
 114 .Pp
 115 The function type and the type of
 116 .Fa bufsize
 117 have changed.
 118 .Sh SEE ALSO
 119 .Xr lstat 2 ,
 120 .Xr stat 2 ,
 121 .Xr symlink 2 ,
 122 .Xr compat 5 ,
 123 .Xr symlink 7
 124 .Sh HISTORY
 125 The
 126 .Fn readlink
 127 function call appeared in
 128 .Bx 4.2 .