lchgrp in PHP

lchgrp — Changes group ownership of symlink
Syntax:

bool lchgrp ( string $filename , mixed $group )
Attempts to change the group of the symlink filename to group.

Only the superuser may change the group of a symlink arbitrarily; other users may change the group of a symlink to any group of which that user is a member.

Parameters:

filename
Path to the symlink.

group
The group specified by name or number.

Return values: Returns TRUE on success or FALSE on failure.



Example #1 Changing the group of a symbolic link

<?php
$target = 'output.php';
$link = 'output.html';
symlink($target, $link);

lchgrp($link, 8);
?>


Note: This function will not work on remote files as the file to be examined must be accessible via the server's filesystem.
Note: When safe mode is enabled, PHP checks whether the files or directories being operated upon have the same UID (owner) as the script that is being executed.
Note: This function is not implemented on Windows platforms.

is_link in PHP

is_link — Tells whether the filename is a symbolic link
Syntax:

bool is_link ( string $filename )
Tells whether the given file is a symbolic link.

Parameters:

filename
Path to the file.

Return values: Returns TRUE if the filename exists and is a symbolic link, FALSE otherwise.



Example #1 Create and confirm if a file is a symbolic link

<?php
$link = 'uploads';

if (is_link($link)) {
    echo(readlink($link));
} else {
    symlink('uploads.php', $link);
}
?>
Errors/Exceptions ¶

Upon failure, an E_WARNING is emitted.



Note: The results of this function are cached. See clearstatcache() for more details.
Tip
As of PHP 5.0.0, this function can also be used with some URL wrappers. Refer to Supported Protocols and Wrappers to determine which wrappers support stat() family of functionality.