| Platform SDK: Windows Sockets |
The Windows Sockets 2 specification defines an extension mechanism that exposes advanced transport functionality to application programs. See the SPI: Function Extension Mechanism in the SPI section. The following Microsoft-specific extensions that were added to Windows Sockets 1.1 are also available to Windows Sockets 2 applications:
These functions are not exported from the Ws2_32.dll; they are exported from Mswsock.dll.
An application written to use the Microsoft-specific extensions to Windows Sockets will not run correctly over a Windows Sockets service provider that does not support those extensions.