Using the Default TPB
From InterBase
Go Up to Creating a Transaction Parameter Buffer
Providing a TPB for a transaction is optional. If one is not provided, then a NULL pointer must be passed to isc_start_transaction() in place of a pointer to the TPB. In this case, InterBase treats a transaction as if the following TPB had been declared for it:
static char isc_tpb[] = {isc_tpb_version3,
isc_tpb_write,
isc_tpb_concurrency,
isc_tpb_wait};