Asynchronous -service provider's responsibilities

diff -r 4816d766a08a -r f345bda72bc4 Symbian3/PDK/Source/GUID-E6D9F8CA-F293-5CE6-93C4-5FEC5EBCB2E9.dita --- a/Symbian3/PDK/Source/GUID-E6D9F8CA-F293-5CE6-93C4-5FEC5EBCB2E9.dita Tue Mar 30 11:42:04 2010 +0100 +++ b/Symbian3/PDK/Source/GUID-E6D9F8CA-F293-5CE6-93C4-5FEC5EBCB2E9.dita Tue Mar 30 11:56:28 2010 +0100 @@ -1,37 +1,37 @@ - - - - - -Asynchronous -service provider's responsibilitiesThis document describes the functionality required from an asynchronous -service provider. -

An asynchronous service provider must interact in the following ways with -its clients:

prior to initiating -a request, a request function must set the value of the passed TRequestStatus to KRequestPending, -which indicates that a request has been issued but not completed.
requests must be completed -by signalling the requesting thread’s request semaphore by calling RThread::RequestComplete() with -the TRequestStatus as the first parameter and the completion -code as the second parameter (which is placed in the TRequestStatus).
there must be a cancel -function which can cancel an outstanding request. In some cases, calling -the cancel function does not cause cancellation because the request is already -complete. In all cases, the request must be complete before the cancel function -returns.
if an asynchronous request -is made, it must complete precisely once, whether normally, abnormally, or -through cancellation.
completion through cancellation -is often indicated by a TRequestStatus code of KErrCancel.