There seems to be some issues yet to be ironed out. Check out the bugs and you might be able to figure out what is the solution to your particular problem.

I dealt with one such error some hours ago, and it turned out that using APC from the SVN trunk was the way to go. Hope this helps!

I've found that you need to clear the opcode cache on each page request otherwise classes that implement interfaces fail to load. This was compiled from the latest svn trunk, Apache 2.4.1, PHP 5.4.0.

Well I'm trying for the last few days, and there is no way I can get an opcode cacher to work with php 5.4. Xcache won't compile, and apc will not recognize certain classes when cached. I think this is the error Simon is talking about.

I heard there were some fixes in the trunk, but I also tried the latest trunk sources, but the same errors keep coming back. I think php without a opcode cacher (there is none available right now) is not production worthy. Hopefull the people at apc will fix this asap.

UPDATE!!!

Xcache 2.0.0-rc1 is out and compatible with php 5.4. Enjoy!

No, APC 1.3.9 (and as of this moment, even the svn trunk) isn't compatible with php 5.4.0, I know because I've just spent hours trying to get it to work (tested various svn/php.ini settings/compiler flags/you name it).

This is just ridiculous, APC is one of the most popular PHP extension and you'd expect after weeks of going through 8 PHP 5.4 RC's they'd have the time to get APC to work along side it.

Pathetic.

It appears that the bug "may" have been fixed in the latest revision to the trunk. I've got it working now with PHP 5.4.0.

svn co http://svn.php.net/repository/pecl/apc/trunk/ apc-trunk

cd apc-trunk

phpize

./configure

make

make install

Zend OPCache included in PHP 5.5

On the 21st March 2013, the PHP 5.5 beta 1 was released including "Zend OPCache" - It looks firmly like this will be the replacement for APC going forward as it is included in the PHP core, and will have to be maintained for each new release.

I would personally advise those who depend on APC for it's opcode caching to test their code with the upcoming built-in opcode cache, and feed back any issues encountered to ensure a stable final release.

I do not know what this means for the future of APC.

APC FOR PHP 5.4+ IS STILL FLAGGED AS BETA

This means the developers do not consider it completely stable. While many people are experiencing no problems at all with the current SVN releases, there is still the odd report of edge cases from people under certain configurations, or under heavy load.

As with everything you would want to use in a production environment, make sure you thoroughly test any release (beta or stable) in development or pre-production environments first. This includes load testing!

As of the 3.1.13 release, commits to the SVN repository have slowed down somewhat and the bug list doesn't have that many recent additions. Make of that what you will.

On 10 December 2012 21:05, Rasmus Lerdorf wrote:

APC is at the point now for 5.4 where I don't think there are any more edge cases than we have in 5.3. Neither is perfect, but it is close enough for the majority of sites.

Anyone with C / gdb skills and some free time is urged to gloss over the bug list and see if they can fix anything, or improve this free open source product that we all rely on.

Alternative solutions exist, Wikipedia provides a list of PHP accelerators.

On the 13th of February 2013, Zeev Suraski announced the availability of the Zend Optimizer+ source code.

There has been quite a lengthy discussion about integrating Zend Optimizer+ into the PHP core in the next major version (the version after 5.5). People may wish to familiarise themselves with Zend Optimizer+ in advance, should this be the case.

Do not use APC 3.1.14

APC 3.1.14 has been removed from PECL downloads due to some serious memory issues that have been discovered but have not yet been tracked down.

If you're already using 3.1.14, you may wish to downgrade until 3.1.15 is released. Remember, this is still beta. If you are using it at all, you are using it at your own risk.

2013-01-02:
APC 3.1.14 is available, adding PHP 5.5 compatibility, in addition to resolving a fair number of other bugs.

Still beta

2012-09-03:
APC 3.1.13 is available, fixing a number of segfaults.

^{2012-08-16:
An APC 3.1.12 tag has been created, but is still marked as beta, its available on the APC PECL page, as well as the changelog.
Lots of bin_dump related bugs fixed this time around.}

^{2012-07-19:
An APC 3.1.11 tag has been created, but is still marked as beta, its available on the APC PECL page, as well as the changelog. I've been following the relevant mailing lists, and they are still actively working on fixing APC bugs however it is a complex module and not many people seem to be up to the task. This release fixes the nasty stat=0 bugs when including files.}

^{2012-04-11:
An APC 3.1.10 tag was created today, and a beta release of 3.1.10 was placed on the APC PECL page
The changelog states:}

• Add PHP 5.4 support (Dmitry, Anatoliy, Pierre)
• ^{_{Fixed bug #22679: Fix apc_bin_dump for constants. Use IS_CONSTANT_TYPE_MASK to handle all the constants, including the unqalified ones (instead of ~IS_CONSTANT_INDEX check)}}
• ^{_{Fixed bug #23822, php crashes on apache restart}}

As of PHP 5.4.7 and APC 3.1.13 (and even APC SVN trunk as of 2012-09-19), although it is "compatible" it is not stable on servers with heavy load, particularly if you're using PHP-FPM and $GLOBALS. Some of the developer discussions on APC talk about unresolved fringe cases.

I'm answering this question 6 months after it was asked because the problem is still prevalent, and encountering this thread w/o an answer like mine is what made me make the leap to PHP 5.4 w/ APC and get burnt. Hopefully this will help people avoid some pain.

APC has a new version: 3.1.14 since 2 January, which resolves some bugs: http://pecl.php.net/package/APC

However, I have been running PHP 5.4.x with APC 3.1.13 from the dotdeb repository without any issues so far, so for me I would say it's stable. dotdeb has also informed me that they will be including the updated APC in the next release of PHP, which is expected to be 5.4.11.

I found apcu http://windows.php.net/downloads/pecl/releases/apcu/

Maybe this is apc for x64 on windows. It (version 4.0.1) worked on my application.

Zend OPCache is included in PHP 5.5 under the name php_opcache.dll in the php/ext directory. In order to activate it:

• Add the php_opcahe.dll file as a zend extension in your php.ini configuration file.
• Use the format zend_extension = path/to/php/ext/php_opcache.dll.
• Place the zend_extension before the xDebug zend_extension in your php.ini config.
• Save your php.ini configuration file and restart your server.

APC - not recommended
Personally I didn't use APC with PHP 5.4 or PHP 5.5, but latest stable APC is not compatible with PHP 5.4, latest beta APC can be used with 5.4 but it is written that still have negative issues with APC.

If you have PHP 5.5
just use Zend Opcache. It is out of the box, so problems are minimum.

If you have PHP 5.4
I recommend XCache. It is fully compatible with PHP 5.4 and 5.5. Actively developed. Last stable version was released 3.5 months ago (10 October 2013). It improves performance even if you use fastcgi.

We are experimenting memory free errors (apache segfault) with PHP 5.4.26 and APC 3.1.9. There's an open bug for APC on PHP 5.4.X: https://bugs.php.net/bug.php?id=61934

I recommend not to use this plugin on PHP > 5.3.

I am using AMPPS with PHP Version 5.5.19. Since some time now exactly from release of PHP 5.5 - APC is replaced with Zend OPCache which is included in PHP 5.5 and up. Now all you have to do to enable "APC" (currently "OPcache") is to edit your php.ini. Before [XDebug] section add the flowing lines:

php.ini

...


[OPcache]


zend_extension=php_opcache.dll


opcache.enable=1
opcache.enable_cli=1
opcache.memory_consumption=512
opcache.interned_strings_buffer=24
opcache.max_accelerated_files=4000
opcache.revalidate_freq=3
opcache.fast_shutdown=1


...

Please note that we need to have two instances of:

zend_extension =

One in [OPcache] and one in [XDebug] section. Xdebug is often not provided as default in your xampp/ampps/easyPHP server installation. You might find yourself in a situation where you will need to download Xdebug extension. You can do this easily by using an online application that defines the right Xdebug for your php. Visit http://xdebug.org/wizard.php and follow their simple instructions. Once you have downloaded the right version of Xdebug for your php version - edit the link of your zend_extension in [XDebug] section.

...


[XDebug]
zend_extension = "C:\Program Files (x86)\Ampps\php\ext\php_xdebug-2.2.6-5.5-vc11.dll"
......

Please note! that you have to add OPcache section before XDebug in your php.ini file!!! If you follow me correctly you should have two instances of zend_extension in your php.ini file (one in OPcache and one in Xdebug section).

This works perfectly for Symfony2 framework, and eliminates recommendation message to install and enable APC for your PHP and Xdebug.

Message to those who run symfony 2 and removed the warning message from "web/config.php", but still encounter a problem by running from command line "php app/check.php". If this happens, that means that your console is using a different php.ini file. Change your system PATH varible - make it point to the right php directory (where you have your php.exe file and which is used by your local server).

If you need deeper explanation let me know in the comment below. Regards.

In XAMPP Version 5.6.3 (PHP 5.6.3) all you have to do in your ini.php is this:

[OPcache]


zend_extension = php_opcache.dll
opcache.enable=1
opcache.enable_cli=1
opcache.memory_consumption=512
opcache.interned_strings_buffer=24
opcache.max_accelerated_files=4000
opcache.revalidate_freq=3
opcache.fast_shutdown=1


[XDebug]


zend_extension = "C:\xampp\php\ext\php_xdebug.dll"
xdebug.max_nesting_level = 200
xdebug.profiler_append = 1
xdebug.profiler_enable = 1
xdebug.profiler_enable_trigger = 0
;xdebug.profiler_output_dir = "C:\xampp\tmp"
;xdebug.profiler_output_name = "cachegrind.out.%t-%s"
;xdebug.remote_enable = 0
;xdebug.remote_handler = "dbgp"
;xdebug.remote_host = "127.0.0.1"
;xdebug.trace_output_dir = "C:\xampp\tmp"

Configuration for symfony2 framework.