### DbEnv::lock_detect

`

###

    #include <db_cxx.h>

    int
    DbEnv::lock_detect(u_int32_t flags, u_int32_t atype, int *rejected);

### Description: DbEnv::lock_detect

The DbEnv::lock_detect method runs one iteration of the deadlock detector. The deadlock detector traverses the lock table and marks one of the participating lock requesters for rejection in each deadlock it finds.

The DbEnv::lock_detect 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.

### Parameters

rejected
  If the rejected parameter is non-NULL, the memory location to which it refers will be set to the number of lock requests that were rejected.
atype
  The atype parameter specifies which lock request(s) to reject. It must be set to one of the following list:
  DB_LOCK_DEFAULT
    Use whatever lock policy was specified when the database environment was created. If no lock policy has yet been specified, set the lock policy to DB_LOCK_RANDOM.
  DB_LOCK_EXPIRE
    Reject lock requests which have timed out. No other deadlock detection is performed.
  DB_LOCK_MAXLOCKS
    Reject the lock request for the locker ID with the most locks.
  DB_LOCK_MAXWRITE
    Reject the lock request for the locker ID with the most write locks.
  DB_LOCK_MINLOCKS
    Reject the lock request for the locker ID with the fewest locks.
  DB_LOCK_MINWRITE
    Reject the lock request for the locker ID with the fewest write locks.
  DB_LOCK_OLDEST
    Reject the lock request for the locker ID with the oldest lock.
  DB_LOCK_RANDOM
    Reject the lock request for a random locker ID.
  DB_LOCK_YOUNGEST
    Reject the lock request for the locker ID with the youngest lock.
flags
  The flags parameter is currently unused, and must be set to 0.

### Errors

The DbEnv::lock_detect method may fail and throw DbException, encapsulating one of the following non-zero errors, or return one of the following non-zero errors:

EINVAL
  An invalid flag value or parameter was specified.

### Class

DbEnv, DbLock

### See Also

Locking Subsystem and Related Methods`

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