inotify_init

(PECL inotify >= 0.1.2)

inotify_init — 初始化 inotify 实例

说明

inotify_init(): resource|false

初始化 inotify_add_watch() 使用的 inotify 实例

参数

此函数没有参数。

返回值

返回资源流或发生错误时返回 false。

示例

示例 #1 inotify 使用示例

<?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);

?>

以上示例的输出类似于：

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() - 添加监听到已初始化的 inotify 实例
inotify_rm_watch() - 移除 inotify 实例的监听
inotify_queue_len() - 如果有待处理事件，返回大于零的数字
inotify_read() - 从 inotify 实例读取事件
fclose() - 关闭一个已打开的文件指针

发现了问题？

了解如何改进此页面 • 提交拉取请求 • 报告一个错误

＋添加备注

用户贡献的备注 1 note

down

david dot schueler at tel-billig dot de ¶

14 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);
}
?>