inotify_init
(PECL inotify >= 0.1.2)
inotify_init — Initialize an inotify instance
说明
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);
}
?>