I try to use the GMP library for big integers in PHP.
I use XAMPP, PHP 5.5.11, and Ubuntu 14.04.
According to several sources it should be as easy as that:
run sudo apt-get install php5-gmp
put extension=php_gmp.so
or extension=gmp.so
in php.ini
restart XAMPP
Then it should work, and in phpinfo() I should see the GMP version.
But nothing works. I also tried the rather unhelpful hints in the installation guide.
What's wrong?