man2/readlink.2

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  32 .\"     @(#)readlink.2  6.8 (Berkeley) 3/10/91
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  34 .\" Modified Sat Jul 24 00:10:21 1993 by Rik Faith (faith@cs.unc.edu)
  35 .\" Modified Tue Jul  9 23:55:17 1996 by aeb
  36 .\" Modified Fri Jan 24 00:26:00 1997 by aeb
  37 .\"
  38 .TH READLINK 2 2007-07-26 "Linux" "Linux Programmer's Manual"
  39 .SH NAME
  40 readlink \- read value of a symbolic link
  41 .SH SYNOPSIS
  42 .B #include <unistd.h>
  43 .sp
  44 .BI "ssize_t readlink(const char *" path ", char *" buf ", size_t " bufsiz );
  45 .sp
  46 .in -4n
  47 Feature Test Macro Requirements for glibc (see
  48 .BR feature_test_macros (7)):
  49 .in
  50 .sp
  51 .ad l
  52 .BR readlink ():
  53 _BSD_SOURCE || _XOPEN_SOURCE\ >=\ 500 || _POSIX_C_SOURCE\ >=\ 200112L
  54 .ad b
  55 .SH DESCRIPTION
  56 .BR readlink ()
  57 places the contents of the symbolic link
  58 .I path
  59 in the buffer
  60 .IR buf ,
  61 which has size
  62 .IR bufsiz .
  63 .BR readlink ()
  64 does not append a null byte to
  65 .IR buf .
  66 It will truncate the contents (to a length of
  67 .I bufsiz
  68 characters), in case the buffer is too small to hold all of the contents.
  69 .SH "RETURN VALUE"
  70 The call returns the count of characters placed in the buffer
  71 if it succeeds, or a \-1 if an error occurs, placing the error
  72 code in
  73 .IR errno .
  74 .SH ERRORS
  75 .TP
  76 .B EACCES
  77 Search permission is denied for a component of the path prefix.
  78 (See also
  79 .BR path_resolution (7).)
  80 .TP
  81 .B EFAULT
  82 .I buf
  83 extends outside the process's allocated address space.
  84 .TP
  85 .B EINVAL
  86 .I bufsiz
  87 is not positive.
  88 .TP
  89 .B EINVAL
  90 The named file is not a symbolic link.
  91 .TP
  92 .B EIO
  93 An I/O error occurred while reading from the file system.
  94 .TP
  95 .B ELOOP
  96 Too many symbolic links were encountered in translating the pathname.
  97 .TP
  98 .B ENAMETOOLONG
  99 A pathname, or a component of a pathname, was too long.
 100 .TP
 101 .B ENOENT
 102 The named file does not exist.
 103 .TP
 104 .B ENOMEM
 105 Insufficient kernel memory was available.
 106 .TP
 107 .B ENOTDIR
 108 A component of the path prefix is not a directory.
 109 .SH "CONFORMING TO"
 110 4.4BSD (the
 111 .BR readlink ()
 112 function call appeared in 4.2BSD),
 113 POSIX.1-2001.
 114 .SH NOTES
 115 In versions of glibc up to and including glibc 2.4, the return type of
 116 .BR readlink ()
 117 was declared as
 118 .IR int .
 119 Nowadays, the return type is declared as
 120 .IR ssize_t ,
 121 as (newly) required in POSIX.1-2001.
 122 .SH "SEE ALSO"
 123 .BR lstat (2),
 124 .BR readlinkat (2),
 125 .BR stat (2),
 126 .BR symlink (2),
 127 .BR path_resolution (7)