Filter Reference

There are two types of functions, as well as several data structures, that make up the ISAPI filter interface.

• Entry-Point Functions: These are functions that your ISAPI filter must provide. These functions are called by IIS.
• Callback Functions: These functions are exposed to your ISAPI filter by IIS. Your filter can use these functions to perform specialized tasks that require the server, such as writing to the client browser.
• Data Structures: These structures are used to communicate between the ISAPI filter and IIS.

All function declarations and data structures are available in the ISAPI filter header file httpfilt.h.