PHP 7.0.6 Released

inotify_init

(PECL inotify >= 0.1.2)

inotify_initInitialize an inotify instance

Description

resource inotify_init ( void )

Initialize an inotify instance for use with inotify_add_watch()

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 $fd
stream_set_blocking($fd0);
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

User Contributed Notes

david dot schueler at tel-billig dot de
5 years ago
Example for tailing a file (like tail -f) using inotify.
<?php
/**
* Tail a file (UNIX only!)
* Watch a file for changes using inotify and return the changed data
*
* @param string $file - filename of the file to be watched
* @param integer $pos - actual position in the file
* @return string
*/
function tail($file,&$pos) {
   
// get the size of the file
   
if(!$pos) $pos = filesize($file);
   
// Open an inotify instance
   
$fd = inotify_init();
   
// Watch $file for changes.
   
$watch_descriptor = inotify_add_watch($fd, $file, IN_ALL_EVENTS);
   
// Loop forever (breaks are below)
   
while (true) {
       
// Read events (inotify_read is blocking!)
       
$events = inotify_read($fd);
       
// Loop though the events which occured
       
foreach ($events as $event=>$evdetails) {
           
// React on the event type
           
switch (true) {
               
// File was modified
               
case ($evdetails['mask'] & IN_MODIFY):
                   
// Stop watching $file for changes
                   
inotify_rm_watch($fd, $watch_descriptor);
                   
// Close the inotify instance
                   
fclose($fd);
                   
// open the file
                   
$fp = fopen($file,'r');
                    if (!
$fp) return false;
                   
// seek to the last EOF position
                   
fseek($fp,$pos);
                   
// read until EOF
                   
while (!feof($fp)) {
                       
$buf .= fread($fp,8192);
                    }
                   
// save the new EOF to $pos
                   
$pos = ftell($fp); // (remember: $pos is called by reference)
                    // close the file pointer
                   
fclose($fp);
                   
// return the new data and leave the function
                   
return $buf;
                   
// be a nice guy and program good code ;-)
                   
break;

                   
// File was moved or deleted
               
case ($evdetails['mask'] & IN_MOVE):
                case (
$evdetails['mask'] & IN_MOVE_SELF):
                case (
$evdetails['mask'] & IN_DELETE):
                case (
$evdetails['mask'] & IN_DELETE_SELF):
                   
// Stop watching $file for changes
                   
inotify_rm_watch($fd, $watch_descriptor);
                   
// Close the inotify instance
                   
fclose($fd);
                   
// Return a failure
                   
return false;
                    break;
            }
        }
    }
}

// Use it like that:
$lastpos = 0;
while (
true) {
    echo
tail($file,$lastpos);
}
?>
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