ISAPI Extension Entry-Point Functions
This section defines the entry-point functions that ISAPI extensions use to expose their functionality to IIS. ISAPI extensions expose their functionality to IIS by providing special entry-point functions, defined in this section. IIS calls these functions to initialize, perform processing in, and terminate your extension.
Both GetExtensionVersion and HttpExtensionProc must be provided by every ISAPI extension. TerminateExtension, called by IIS just before the extension is unloaded, is considered optional, although you should provide this function if your extension needs to free any allocated or locked resources before being unloaded.
This section includes the following topics: