PHP | is_link( ) Function

The is_link() function in PHP used to check whether the specified file is a symbolic link or not. The path to the file is sent as a parameter to the is_link() function and it returns TRUE if the filename exists and is a symbolic link, otherwise it returns FALSE.

Syntax:

is_link(file)

Parameters Used:
The is_link() function in PHP accepts only one parameter.

• file : It is a mandatory parameter which specifies the path of the file.

Return Values:
It returns TRUE if the filename exists and is a symbolic link, otherwise it returns FALSE.

Exceptions:

1. An E_WARNING is emitted on failure.
2. The result of this function are cached and therefore the clearstatcache() function is used to clear the cache.

Examples:

Input : $mylink = "gfg";
        if(is_link($mylink))
        {
         echo ("$mylink is a symbolic link!");
        }
        else
        {
         echo ("$mylink is not a symbolic link!");
        }

Output : gfg is a symbolic link!

Input : $mylink = "gfg";
        if (is_link($mylink)) 
        {
         echo ("$mylink is a symbolic link!");
         echo "Reading the link :\n";
         echo(readlink($mylink));
        }
        else 
        {
         symlink("gfg", $mylink);
        }
Output : gfg is a symbolic link!
         Reading the link :
         A portal for geeks!

Below programs illustrate the is_link() function.

Program 1

<?php

$myfile = "gfg";

// checking whether the file is a symbolic link or not
if (is_link($mylink)) {
    echo ("$mylink is a symbolic link!");
} else {
    echo ("$mylink is not a symbolic link!");
}

?>

Output:

gfg is a symbolic link!

Program 2

<?php

$myfile = "gfg";

// checking whether the file
// is a symbolic link or not
if (is_link($mylink)) {
    echo ("$mylink is a symbolic link!");

    // Reading the link
    echo "Reading the link :\n";
    echo (readlink($mylink));
}

// creating a symbolic link of the
// file if it doesn't exist
else {
    symlink("gfg", $mylink);
}

?>

Output:

gfg is a symbolic link!
Reading the link :
A portal for geeks!

Reference:
http://php.net/manual/en/function.is-link.php