It can be installed as a PECL

benf — Wed, 29 Sep 2010 15:07:30 +0000

It can be installed as a PECL package or a php extention.

I was also under the impression that HASH_HMAC is part of php5, I am using Gentoo which may be installed slightly differently.

I check php.ini.

That's interesting because

pr0gr4mm3r — Tue, 28 Sep 2010 00:25:21 +0000

That's interesting because according to http://us2.php.net/manual/en/hash.installation.php, that function is a part of the PHP core. Are you running PHP in safe mode by chance?

The function works on my server, and I don't see any configuration settings in my Apache compile options - both php.ini and WHM's EasyApache.

I found on Stack Overflow that somebody mentioned it's a PECL package ("hash"), but that sorta conflicts with what the PHP manual says.

benf — Mon, 27 Sep 2010 09:40:51 +0000

WE are using a dedicated server so I have all control running php5 on gentoo

pr0gr4mm3r — Sun, 26 Sep 2010 23:00:29 +0000

Couple questions to further assist:

What version of PHP are you using?
How much control do you have over your server (do you have a dedicated server, shared hosting, etc)?

It seems that some hosts may disable this function, but there are custom implementations defined in the link above.