MCAL stands for Modular Calendar Access Library.
Libmcal is a C library for accessing calendars. It's written to be
very modular, with pluggable drivers. MCAL is the calendar
equivalent of the IMAP module for mailboxes.
With mcal support, a calendar stream can be opened much like the
mailbox stream with the IMAP support. Calendars can be local file
stores, remote ICAP servers, or other formats that are supported
by the mcal library.
Calendar events can be pulled up, queried, and stored. There is
also support for calendar triggers (alarms) and recurring events.
With libmcal, central calendar servers can be accessed,
removing the need for any specific database or local file
Most of the functions use an internal event structure that is
unique for each stream. This alleviates the need to pass around
large objects between functions. There are convenience functions
for setting, initializing, and retrieving the event structure
This extension has been moved to the PECL repository and is no longer bundled with
PHP as of PHP 5.0.0.
PHP had an ICAP extension previously, but the original library
and the PHP extension is not supported anymore. The suggested
replacement is MCAL.