Using isc prepare transaction2()
Like isc_prepare_transaction(), isc_prepare_transaction2() performs the first phase of a two-phase commit, except that isc_prepare_transaction2() enables an application to supply its own transaction description for insertion into the RDB$TRANSACTION_DESCRIPTION field of the RDB$TRANSACTION system table.
Important: Do not use this call without first examining and understanding the information InterBase stores in RDB$TRANSACTION_DESCRIPTION during an automatic, twophase commit. Storage of improper or incomplete information can prevent database recovery if the two-phase commit fails.
See isc_prepare_transaction2() in the API Function Reference chapter for the complete syntax.