Where does the mysqli extension find the default connection charset?

Hello there, I'd like to know which configuration file or setting is used by PHP mysqli extension to know the default charset connection to the database. I have two boxes with MySQL 5 / PHP 5 on them. One is a Gentoo box, and on this one by default the connection happens in UTF-8. The other server is a Mac OS X box and it uses latin-1 by default (forcing me to switch manually). I thought the information would be in /etc/my.cnf (in the client charset line), but this file is on OS X and it does not work. The only thing I could see that PHP is using is some locale settings, because on Gentoo locale prints LANG=en_US.UTF-8 LC_CTYPE="en_US.UTF-8" LC_NUMERIC="en_US.UTF-8" LC_TIME="en_US.UTF-8" LC_COLLATE="en_US.UTF-8" LC_MONETARY="en_US.UTF-8" LC_MESSAGES="en_US.UTF-8" LC_PAPER="en_US.UTF-8" LC_NAME="en_US.UTF-8" LC_ADDRESS="en_US.UTF-8" LC_TELEPHONE="en_US.UTF-8" LC_MEASUREMENT="en_US.UTF-8" LC_IDENTIFICATION="en_US.UTF-8" LC_ALL= whereas on OS X locale prints: LANG= LC_COLLATE="C" LC_CTYPE="C" LC_MESSAGES="C" LC_MONETARY="C" LC_NUMERIC="C" LC_TIME="C" LC_ALL="C" So could anyone experienced in the mysqli extension can help me so that I can set the default charset for the connection to be utf-8 on my OS X box? Thanks Jean-Noël