The DbEnv::lock_id method
copies a locker ID, which is guaranteed to be unique in the specified lock
table, into the memory location referenced by idp.
The DbEnv::lock_id method either returns a non-zero error value or throws an exception that
encapsulates a non-zero error value on failure, and returns 0 on success.
Errors
The DbEnv::lock_id method may fail and throw an exception or return a non-zero error for errors specified for other Berkeley DB and C library or system methods.
If a catastrophic error has occurred, the DbEnv::lock_id method may fail and either
return DB_RUNRECOVERY or throw an exception encapsulating
DB_RUNRECOVERY, in which case all subsequent Berkeley DB calls will fail
in the same way.