inotify_init

(PECL inotify >= 0.1.2)

inotify_init — Initialize an inotify instance

说明

resource inotify_init ( void )

Initialize an inotify instance for use with inotify_add_watch()

返回值

A stream resource or FALSE on error.

范例

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 );

 ?>

以上例程的输出类似于：

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)
  ),
);

参见

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() - 关闭一个已打开的文件指针

用户评论:

[#1] david dot schueler at tel-billig dot de [2010-11-25 08:42:25]

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); } ?>