Sign up ×
Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

When calling a gmp math function like gmp_mod, I get:

Fatal error: Call to undefined function gmp_mod()

I have installed the php5-gmp package and restarted the web-server, and the function is still undefined. The server is running Ubuntu 10.04 and PHP is running as an Apache module. All software was installed from official packages.

How do I enable the GMP math functions in PHP? I'm looking for a solution that uses official packages, not compiling from source.

share|improve this question

1 Answer 1

Here is the way which worked for me :

  1. Installed GMP with apt-get install php5-gmp
  2. Added to php.ini

Et voilà !

phpinfo() sample :

gmp support     enabled
GMP version     4.3.2 

It works fine here (Debian), so I suppose it will be ok for Ubuntu too.

share|improve this answer
On Ubuntu 12.04 LTS, I needed to use, not I also needed to restart Apache for the changes to take effect (not surprising as I'm using mod_php). –  Calrion Jan 26 '14 at 23:52
In my case sudo apt-get install php5-gmp automatically updated php.ini and restarted Apache. –  KalenGi Dec 3 '14 at 23:52

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.