Does PHP have the equivilant to Java 'synchronized' , or is this not required?

Question

I am familiar with Java and at the moment I am teaching myself PHP. To prevent race conditions and deadlocks, Java uses the keyword 'synchronized'.

From Oracle docs:

public synchronized void increment() {
        c++;
}

I am using prepared statements within a separate class to access my database. I wish to avoid race conditions, deadlocks etc, but I cannot see how PHP handles this.

Does PHP have the equivalent to Java, and is it operating system specific? I am using Windows. What would best practices be?

score 5 · Answer 1 · answered Jan 10 '12 at 19:10

5

PHP doesn't do threads. Don't worry about it*.

I'm positive there are reasons that you might be worried about deadlocks and raceconditions, but only if you're handling a large application across many front-ends communicating with the same back-end.

But, like, yeah, don't worry about it.

answered Jan 10 '12 at 19:10

tkone

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The PHP documentation disagrees with you. http://php.net/manual/en/class.thread.php – Luke A. Leber Jan 22 '17 at 04:05
@LukeA.Leber you do realize the answer is over 5 years old, and answered 2 years PRIOR to pthreads being added as PECL extension? Release 0.0.33 (alpha) was 9/25/2012 and the extension isn't marked stable until March 2014? – tkone Jan 22 '17 at 20:01
Nope, didn't have a clue. – Luke A. Leber Jan 22 '17 at 23:42

score 1 · Answer 2 · answered Jan 10 '12 at 19:13

1

In a single threaded application this is no a problem. For the database situation however, I would go with transactions. Transactions will basically do what you would expect fron the synchronized - do several operations in one atomic operation, either all succeed or all failed.l

answered Jan 10 '12 at 19:13

Dmitri Snytkine

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Thanks for the advise Dmitri I will investigate Transactions! – Alan Jan 10 '12 at 19:19

score 1 · Answer 3 · answered Jan 10 '12 at 19:21

1

The PHP-file is not run in parallel so within one instance not using the function pcntl-fork a race-condition cannot occur. When you are looking at the side of MySQL, it is fully parallel.

answered Jan 10 '12 at 19:21

Gustav

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could there be an issue from MySQL? or am I missing the point? – Alan Jan 10 '12 at 19:24
MySQL is fully async, so no problem. The PHP-script is run from top to bottom so just think of it as a food-recipe or something. ;) – Gustav Jan 10 '12 at 19:29

score 0 · Answer 4 · answered Feb 24 '13 at 06:56

I think the sem_acquire is the best way to do it. "blocks (if necessary) until the semaphore can be acquired. A process attempting to acquire a semaphore which it has already acquired will block forever if acquiring the semaphore would cause its maximum number of semaphore to be exceeded. " http://us3.php.net/manual/en/function.sem-acquire.php

score 0 · Answer 5 · answered Dec 29 '15 at 20:55

If you are writing a multithreaded application you can use the pthreads extension and your objects that are intended for multi-threaded use should extend the Threaded class which has a synchronized method.

The pthreads extension is not operating system specific but requires the ZTS (Zend Thread Safety) build of PHP.

score 0 · Answer 6 · answered Sep 02 '16 at 15:28

0

yes, with Process Control Extensions http://php.net/manual/ru/threaded.synchronized.php

answered Sep 02 '16 at 15:28

Artkom

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score -1 · Accepted Answer · answered Jan 10 '12 at 19:12

-1

No, your best bet is to use a "lock", in this case a file lock.

See http://us3.php.net/flock for more information on file locking.

answered Jan 10 '12 at 19:12

Nick Garvey

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Does PHP have the equivilant to Java 'synchronized' , or is this not required?

7 Answers7

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