ISAPI Filter Entry-Point Functions
This section defines the entry-point functions that ISAPI filters use to expose their functionality to IIS. IIS calls these functions to initialize, notify, or terminate ISAPI filters.
Both GetFilterVersion and HttpFilterProc must be provided by every ISAPI filter. The TerminateFilter function is called by IIS just before the filter is unloaded. This function is optional, although you should consider providing it if the ISAPI filter you are using needs to free any allocated or locked resources before being unloaded.
This section includes the following topics: