User Contributed Notes

casinero dot triste at OH_NO_SPAM dot gmail dot com 29-Jul-2017 08:40
A little function to readlink TO THE END:
(realpath can't do this if the symlink (ultimately) points to a non-existing path, since it just returns false in this case.)

function readlinkToEnd($linkFilename) {
  if(!is_link($linkFilename)) return $linkFilename;
  $final = $linkFilename;
  while(true) {
    $target = readlink($final);
    if(substr($target, 0, 1)=='/') $final = $target;
    else $final = dirname($final).'/'.$target;
    if(substr($final, 0, 2)=='./') $final = substr($final, 2);
    if(!is_link($final)) return $final;
  }
}
casinero dot triste at OH_NO_SPAM dot gmail dot com 29-Jul-2017 08:35
A little function to readlink TO THE END:
(realpath can't do this if the symlink (ultimately) points to a non-existing path, since it just returns false in this case.)

function readlinkToEnd($linkFilename) {
  if(!is_link($linkFilename)) return $linkFilename;
  $final = $linkFilename;
  while(true) {
    $target = readlink($final);
    if(substr($target, 0, 1)=='/') $final = $target;
    else $final = dirname($final).'/'.$target;
    if(substr($final, 0, 2)=='./') $final = substr($final, 2);
    if(!is_link($final)) return $final;
  }
}
ayon at hyurl dot com 09-Mar-2017 04:38
It is neccesary to be notified that readlink only works for a real link file, if this link file locates to a directory, you cannot detect and read its contents, the is_link() function will always return false and readlink() will display a warning is you try to do. Like the following codes:
<?php
//assume that A is a directory located in C:, B is a symlink to A, and A contents a file named C.
echo is_link('B/C'); //false
echo readlink('B/C'); //false and a warning will be displayed
//instead, you should use realpath() function to get the real path of C
echo realpath('B/C'); //C:\A\C
?>
MarkAndrewSlade at gmail dot com 10-Jun-2009 12:35
This will trigger a warning and return false if you pass it a non-symlink.  If the file doesn't exist, it will trigger a differently worded warning.

mslade@jupiter ~$ touch a
mslade@jupiter ~$ ln -s a b
mslade@jupiter ~$ ls -l {a,b}
-rw------- 1 mslade mslade 0 2009-06-10 15:27 a
lrwxrwxrwx 1 mslade mslade 1 2009-06-10 15:27 b -> a
mslade@jupiter ~$ php -r "var_dump(readlink('b'));"
string(1) "a"
mslade@jupiter ~$ php -r "var_dump(readlink('a'));"

Warning: readlink(): Invalid argument in Command line code on line 1
bool(false)
mslade@jupiter ~$ php -r "var_dump(readlink('c'));"

Warning: readlink(): No such file or directory in Command line code on line 1
bool(false)
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