User`s guide

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WinHLLAPIAsync( )
This function provides an asynchronous flavor to the following HLLAPI functions:
STARTKSINTERCEPT, WAIT, STARTHOSTNOTIFICATION, STARTCLOSEINTERCEPT,
SENDFILE, and RECEIVEFILE. You should use WinHLLAPIAsync( ) instead of the blocking
versions of these functions.
HANDLE WinHLLAPIAsync(hWnd,lpwFunction,lpbyString,lpwLength,
lpwReturnCode);
When the asynchronous operation is complete, the application’s window hWnd receives the message
returned by RegisterWindowMessage with “WinHLLAPIAsync” or
“WinHLLAPIAsyncFileTransfer” as the input string. For STARTKSINTERCEPT, WAIT,
STARTHOSTNOTIFICATION, and STARTCLOSEINTERCEPT, The wParam argument contains the
asynchronous task handle as returned by the original function call. The high 16 bits of lParam contain
any error code. The error code may be any error as defined in WHLLAPI.H. An error code of zero
indicates successful completion of the asynchronous function. The low 16 bits contains the original
function number. For SENDFILE and RECEIVEFILE, the wParam and lParam contain status
information. See the Asynchronous Mode section of Send File and Receive File for details.
The return value specifies whether the asynchronous resolution request was successful.
It is nonzero if the operation was successful and the actual return value is an asynchronous task handle
that can be subsequently used to cancel the asynchronous resolution request if necessary. It is zero if
the function failed.
The asynchronous function can be canceled at any time by passing the handle returned by
WinHLLAPIAsync to WinHLLAPICancelAsyncRequest( ).
Windows HLLAPI Supplier Notes
The Windows HLLAPI supplier must ensure that messages are successfully posted to the application.
If a PostMessage( ) operation fails, the Windows HLLAPI implementation must re-post that message.
See also: WinHLLAPICancelAsyncRequest( )
Syntax
Returns