ISAPI Extension Callback Functions

This section describes the callback functions that an ISAPI extension uses to pass information to and from IIS about server variables, request and response data, and connection status.

ISAPI extensions communicate with IIS through the EXTENSION_CONTROL_BLOCK structure. After the main entry point for an ISAPI extension, HttpExtensionProc, is called with a pointer to the EXTENSION_CONTROL_BLOCK structure, the ISAPI extension can use callback functions, defined in this section, to communicate with IIS.

The PFN_HSE_IO_COMPLETION function is different than the other ISAPI callback functions because it must be exposed by an ISAPI extension that performs asynchronous I/O operations.

This section includes the following topics:

• GetServerVariable Function

• PFN_HSE_IO_COMPLETION Function

• ReadClient Function

• ServerSupportFunction Function

• WriteClient Function