I have a Slackware 8.1 installation and I recently downloaded the php-4.3.1 upgrade from the Slackware Web site. After installation, I found that my PHP scripts that used to access a MySQL database were no longer functioning. They were working properly prior to the upgrade.

The cause, as it turns out, is that this compilation of PHP does not integrate the MySQL module into the main code base. Therefore, the MySQL dynamic load library has to be explicitly specified in php.ini. As it turns out, I also needed to change a PHP directive that specifies the location of extension modules:

extension_dir = /usr/lib/php/extensions/

With these changes, upon restarting the Apache server, PHP and MySQL were working correctly.