FAQ

• General
• Users
• Contributors

General

What is the history of HHVM?

For a history of what is now HHVM, please visit our Wikipedia page

How does Facebook use and run HHVM?

Facebook's entire desktop site runs on HHVM.

What platforms is HHVM supported on?

• Linux: HHVM has broad support on various flavors of Linux (Ubuntu, Debian, CentOS)
• Mac OS X: HHVM has some support for Mac OS X. It runs in interpreted mode only right now (no JITted code).
• Windows: There is no support for HHVM on Windows currently.

What is the roadmap for HHVM?

Are there are any videos, presentations, etc. about HHVM?

For a discussion about HHVM and its benefits, please see [this PHP UK Conference 2013 presentation] (http://www.youtube.com/watch?v=Dwek7dZDFN0) For a deep dive into the HHVM internals, please see this QCon 2012 presentation. Other information can be found in the references of our Wikipedia page.

Who are the key players on the HHVM team?

You can see a list of common contributors to HHVM [on the Github contributors page]. Key people include Sara Golemon, Paul Tarjan and Sean Cannella.

Users

How do I install HHVM? Where are the binaries?

On various flavors of Linux, HHVM can be installed from pre-packaged binaries or built from the HHVM source code. The pre-packaged binaries can be behind the source code builds in terms of functionality and bug fixes on the order of weeks.

HHVM on Mac OS X can currently only be built from the source code.

How do I configure HHVM? What are my options?

What code does HHVM currently run?

What is known to be broken with HHVM?

What do I do if I run into a problem (e.g., an error, fatal or segfault)?

Please submit an issue.

Other areas for discussion and support are on #hhvm on IRC, HHVM on Facebook

When is HHVM going to run my code?

When will HHVM support Apache?

What PHP extensions does HHVM currently support?

The list of supported extensions can be found in the extensions directory of the hhvm codebase: https://github.com/facebook/hiphop-php/tree/master/hphp/runtime/ext

Contributors

How do I contribute to HHVM?

What is the HHVM team currently working on?

I want to port extensions to HHVM. How do I do that?

Where are ported extensions located in the codebase?

What is the process for committing code to HHVM?

How do I test code that I write for HHVM?

Tests are written in the same format as Zend PHP.

• One .php file containing the test (example)
• One of a .php.expect, .php.expectf, or .php.expectregex file (example)

A test is generally put in the hphp/test/[quick | slow] directory and run with the test runner script hphp/test/run (e.g., hphp/test/run/ test/quick runs all the tests in the quick directory).

See the test readme for further information.

Where are the technical specifications for the HHVM runtime (e.g., bytecode spec)?

All of the HHVM technical specifications are located in the hphp/doc directory. Some specifications of interest are:

• Command line options when running hhvm
• Options for HHVM when running a program
• Bytecode specification

I need a feature, but don't know how to implement it? What can I do to get this feature into HHVM?