If a lock cannot be granted because the requested lock conflicts with an
existing lock, return immediately instead of waiting for the lock to
become available.
The obj argument is an untyped byte string that specifies the
object to be locked or released.
A lock was requested that could not be immediately granted and the
flags parameter was set to DB_LOCK_NOWAIT.
Otherwise, the lock_get function returns a non-zero error value on failure and 0 on success.
Errors
The lock_get function may fail and return a non-zero error for the following conditions:
DB_LOCK_DEADLOCK
The operation was selected to resolve a deadlock.
EINVAL
An invalid flag value or parameter was specified.
ENOMEM
The maximum number of locks has been reached.
The lock_get function may fail and return a non-zero error for errors specified for other Berkeley DB and C library or system functions.
If a catastrophic error has occurred, the lock_get function may fail and return
DB_RUNRECOVERY, in which case all subsequent Berkeley DB calls will fail
in the same way.