CCVS is Red Hat's credit card verification system, enabling financial transactions to be processed by your programs. This is not free software; you need to buy it from Red Hat and have it installed and working on your system before you can use the PHP API for it. A demo download is available for testing only.
The CCVS home page is at http://www.redhat.com/products/software/ecommerce/ccvs/.
Once you have the software installed and working, to enable it in PHP you must pass the --with-ccvs=[DIR] option (where DIR is the base CCVS installation directory) to the configure script and rebuild PHP. The extension may also be available as a loadable module, meaning that you don't need to rebuild PHP, but can simply load the extension using the dl() function or via the PHP initialization file.
Also note that your PHP and ccvsd processes must be running as the same user. You may want to have a separate httpd running on a special port as the ccvs user.
PHP Functions Essential Reference. Copyright © 2002 by New Riders Publishing (Authors: Zak Greant, Graeme Merrall, Torben Wilson, Brett Michlitsch). This material may be distributed only subject to the terms and conditions set forth in the Open Publication License, v1.0 or later (the latest version is presently available at http://www.opencontent.org/openpub/). The authors of this book have elected not to choose any options under the OPL. This online book was obtained from http://www.fooassociates.com/phpfer/ and is designed to provide information about the PHP programming language, focusing on PHP version 4.0.4 for the most part. The information is provided on an as-is basis, and no warranty or fitness is implied. All persons and entities shall have neither liability nor responsibility to any person or entity with respect to any loss or damage arising from the information contained in this book.