[in] Whether the commit is retaining or nonretaining.
A retaining commit or abort should not change the characteristics (isolation level, isolation flags, transaction options) of the transaction. The new unit of work retains the same characteristics as the committed work.
[in] Values taken from the enumeration XACTTC. Values that may be specified in grfTC are as follows. These values are mutually exclusive.
When this flag is specified, an asynchronous commit is performed.
When this flag is specified, the call to ITransaction::Commit returns after phase one of the two-phase commit protocol.
When this flag is specified, the call to ITransaction::Commit returns after phase two of the two-phase commit protocol.