Initialize an inotify instance

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- PHP Manual
- Inotify Functions
- Initialize an inotify instance

# inotify_init

(PECL inotify >= 0.1.2)

inotify_init — Initialize an inotify instance

### Description

inotify_init(): resource|false

Initialize an inotify instance for use with inotify_add_watch()

### Parameters

This function has no parameters.

### Return Values

A stream resource or `false` on error.

### Examples

Example #1 Example usage of inotify

    <?php
    // Open an inotify instance
    $fd = inotify_init();

    // Watch __FILE__ for metadata changes (e.g. mtime)
    $watch_descriptor = inotify_add_watch($fd, __FILE__, IN_ATTRIB);

    // generate an event
    touch(__FILE__);

    // Read events
    $events = inotify_read($fd);
    print_r($events);

    // The following methods allows to use inotify functions without blocking on inotify_read():

    // - Using stream_select() on $fd:
    $read = array($fd);
    $write = null;
    $except = null;
    stream_select($read,$write,$except,0);

    // - Using stream_set_blocking() on $fd
    stream_set_blocking($fd, 0);
    inotify_read($fd); // Does no block, and return false if no events are pending

    // - Using inotify_queue_len() to check if event queue is not empty
    $queue_len = inotify_queue_len($fd); // If > 0, inotify_read() will not block

    // Stop watching __FILE__ for metadata changes
    inotify_rm_watch($fd, $watch_descriptor);

    // Close the inotify instance
    // This may have closed all watches if this was not already done
    fclose($fd);

    ?>

The above example will output something similar to:

    array(
      array(
        'wd' => 1,     // Equals $watch_descriptor
        'mask' => 4,   // IN_ATTRIB bit is set
        'cookie' => 0, // unique id to connect related events (e.g.
                       // IN_MOVE_FROM and IN_MOVE_TO events)
        'name' => '',  // the name of a file (e.g. if we monitored changes
                       // in a directory)
      ),
    );

### See Also

- inotify_add_watch() - Add a watch to an initialized inotify instance
- inotify_rm_watch() - Remove an existing watch from an inotify instance
- inotify_queue_len() - Return a number upper than zero if there are pending events
- inotify_read() - Read events from an inotify instance
- fclose() - Closes an open file pointer