These functions interface the CCVS API, allowing you to work directly with CCVS from your PHP scripts. CCVS is RedHat's solution to the "middle-man" in credit card processing. It lets you directly address the credit card clearing houses via your *nix box and a modem. Using the CCVS module for PHP, you can process credit cards directly through CCVS via your PHP Scripts. The following references will outline the process.
Note: CCVS has been discontinued by Red Hat and there are no plans to issue further keys or support contracts. Those looking for a replacement can consider MCVE by Main Street Softworks as a potential replacement. It is similar in design and has documented PHP support!
To enable CCVS Support in PHP, first verify your CCVS installation directory. You will then need to configure PHP with the --with-ccvs option. If you use this option without specifying the path to your CCVS installation, PHP will attempt to look in the default CCVS Install location (/usr/local/ccvs). If CCVS is in a non-standard location, run configure with: --with-ccvs=$ccvs_path, where $ccvs_path is the path to your CCVS installation. Please note that CCVS support requires that $ccvs_path/lib and $ccvs_path/include exist, and include cv_api.h under the include directory and libccvs.a under the lib directory.
Additionally, a ccvsd process will need to be running for the configurations you intend to use in your PHP scripts. You will also need to make sure the PHP Processes are running under the same user as your CCVS was installed as (e.g. if you installed CCVS as user 'ccvs', your PHP processes must run as 'ccvs' as well.)
Additional information about CCVS can be found at http://www.redhat.com/products/ccvs. RedHat maintains slightly outdated but still useful documentation at http://www.redhat.com/products/ccvs/support/CCVS3.3docs/ProgPHP.html.