Read value of a symbolic link
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    • PHP Manual
    • Eio Functions
    • Read value of a symbolic link

    eio_readlink

    (PECL eio >= 0.0.1dev)

    eio_readlink — Read value of a symbolic link

    Description

    eio_readlink(
        string $path,
        int $pri,
        callable $callback,
        mixed $data = NULL
    ): resource

    Parameters

    path

    Source symbolic link path

    pri

    The request priority: EIO_PRI_DEFAULT, EIO_PRI_MIN, EIO_PRI_MAX, or null. If null passed, pri internally is set to EIO_PRI_DEFAULT.

    callback

    callback function is called when the request is done. It should match the following prototype:

    void callback(mixed $data, int $result[, resource $req]);
    data

    is custom data passed to the request.

    result

    request-specific result value; basically, the value returned by corresponding system call.

    req

    is optional request resource which can be used with functions like eio_get_last_error().

    data

    Arbitrary variable passed to callback.

    Return Values

    eio_readlink() returns request resource on success, or false on failure.

    Examples

    Example #1 eio_readlink() example

    <?php
    $filename = dirname(__FILE__)."/symlink.dat";
    touch($filename);
    $link = dirname(__FILE__)."/symlink.link";
    $hardlink = dirname(__FILE__)."/hardlink.link";
    
    function my_hardlink_cb($data, $result) {
        global $link, $filename;
        var_dump(file_exists($data) && !is_link($data));
        @unlink($data);
    
        eio_symlink($filename, $link, EIO_PRI_DEFAULT, "my_symlink_cb", $link);
    }
    
    function my_symlink_cb($data, $result) {
        global $link, $filename;
        var_dump(file_exists($data) && is_link($data));
    
        if (!eio_readlink($data, EIO_PRI_DEFAULT, "my_readlink_cb", NULL)) {
            @unlink($link);
            @unlink($filename);
        }
    }
    
    function my_readlink_cb($data, $result) {
        global $filename, $link;
        var_dump($result);
    
        @unlink($link);
        @unlink($filename);
    }
    
    eio_link($filename, $hardlink, EIO_PRI_DEFAULT, "my_hardlink_cb", $hardlink);
    eio_event_loop();
    ?>

    The above example will output something similar to:

    bool(true)
    bool(true)
    string(16) "/tmp/symlink.dat"

    See Also

    • eio_symlink() - Create a symbolic link