SplFileObject::flock

(PHP 5 >= 5.1.0, PHP 7, PHP 8)

SplFileObject::flockPortable file locking

Descrizione

public SplFileObject::flock(int $operation, int &$wouldBlock = null): bool

Locks or unlocks the file in the same portable way as flock().

Elenco dei parametri

operation

operation is one of the following:

  • LOCK_SH to acquire a shared lock (reader).
  • LOCK_EX to acquire an exclusive lock (writer).
  • LOCK_UN to release a lock (shared or exclusive).

It is also possible to add LOCK_NB as a bitmask to one of the above operations, if flock() should not block during the locking attempt.

wouldBlock

Set to true if the lock would block (EWOULDBLOCK errno condition).

Valori restituiti

Restituisce true in caso di successo, false in caso di fallimento.

Esempi

Example #1 SplFileObject::flock() example

<?php
$file
= new SplFileObject("/tmp/lock.txt", "w");
if (
$file->flock(LOCK_EX)) { // do an exclusive lock
$file->ftruncate(0); // truncate file
$file->fwrite("Write something here\n");
$file->flock(LOCK_UN); // release the lock
} else {
echo
"Couldn't get the lock!";
}
?>

Vedere anche:

  • flock() - Sistema di bloccaggio file

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User Contributed Notes 2 notes

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4
digitalprecision at gmail dot com
13 years ago
For the record, the example given here has an explicit command to truncate the file, however with a 'write mode' of 'w', it will do this for you automatically, so the truncate call is not needed.
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0
Ahmed Rain
2 years ago
@digitalprecision What you said is not completely true, ftruncate(0); is needed if there was a write to the file before the lock is acquired. You also may need fseek(0); to move back the file pointer to the beginning of the file

<?php
$file
= new SplFileObject("/tmp/lock.txt", "w");
$file->fwrite("xxxxx"); // write something before the lock is acquired
sleep(5); // wait for 5 seconds

if ($file->flock(LOCK_EX)) { // do an exclusive lock
   
$file->fwrite("Write something here\n");
   
$file->flock(LOCK_UN);   // release the lock   
} else {
    echo
"Couldn't get the lock!";
}
?>

"lock.txt" content:

xxxxxWrite something here
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