On Ubuntu 13.10 you have to install this extension first (PHP 5.5.3):
apt-get install php5-json
(Don't forget to restart web server.)
As of PHP 5.2.0, the JSON extension is bundled and compiled into PHP by default.
Information for installing this PECL extension may be found in the manual chapter titled Installation of PECL extensions. Additional information such as new releases, downloads, source files, maintainer information, and a CHANGELOG, can be located here: ยป http://pecl.php.net/package/json
On Ubuntu 13.10 you have to install this extension first (PHP 5.5.3):
apt-get install php5-json
(Don't forget to restart web server.)
On one server I use (FreeBSD 6.3; PHP 5.2.6 as module in Apache 2.2.10), PHP was compiled with the '--disable-all' configuration option. Consequently, there exists a secondary configuration file -- /usr/local/php5/etc/extensions.ini -- in which the line
; extension=json.so
must be uncommented (delete the semicolon) and Apache restarted for these functions to be available.
On RHEL5/CentOS5 add the EPEL repository (http://fedoraproject.org/wiki/EPEL).
After that, installation is as simple as:
sudo yum install php-pecl-json