فункциة flock() في PHP
التعريف والاستخدام
فункциة flock() قفل أو إطلاق ملف.
إذا نجح، فإنه يعود إلى true. إذا فشل، فإنه يعود إلى false.
القواعد
flock(file,lock,block)
| المعلمات | وصف |
|---|---|
| file | مطلوب. يحدد الملف المفتوح الذي سيتم قفله أو إطلاقه. |
| lock | مطلوب. يحدد نوع القفل الذي سيتم استخدامه. |
| block | اختياري. إذا تم تعيينه إلى 1 أو true، فإنه يمنع عملية أخرى عند القفل. |
说明
The operation of flock() file It must be a file pointer that has already been opened.
lock The parameter can be one of the following values:
- To obtain a shared lock (reading program), set lock to LOCK_SH (set to 1 in versions before PHP 4.0.1).
- To obtain an exclusive lock (writing program), set lock to LOCK_EX (set to 2 in versions before PHP 4.0.1).
- To release the lock (whether shared or exclusive), set lock to LOCK_UN (set to 3 in versions before PHP 4.0.1).
- If you do not want flock() to block during locking, set lock Add LOCK_NB (set to 4 in versions before PHP 4.0.1).
提示和注释
提示：Can be used fclose() To release the locking operation, it will also be automatically called when the code execution is completed.
注释：Since flock() requires a file pointer, it may be necessary to use a special locking file to protect access to the file intended to be opened in write mode (add "w" or "w+" in the fopen() function).
实例
<?php
$file = fopen("test.txt","w+");
// exclusive locking
if (flock($file,LOCK_EX))
{
fwrite($file,"Write something");
// release lock
flock($file,LOCK_UN);
}
else
{
echo "Error locking file!";
}
fclose($file);
?>
