WinHLLAPI is based on the familiar EHLLAPI.API. It encompasses all of the existing functionality and adds extensions that take advantage of the Windows message driven environment. Users of the HCL Z and I Emulator for Windows EHLLAPI interface will notice no functional difference unless they incorporate the WinHLLAPI extensions.

The WinHLLAPI extension functions and any functions that deviate from the EHLLAPI form are described in WinHLLAPI Extension Functions. For information on common functions, refer to EHLLAPI Functions.