Library Version 12.1.6.2

DB_ENV->cdsgroup_begin()
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## DB_ENV->cdsgroup_begin()

    #include <db.h>

    int
    DB_ENV->cdsgroup_begin(DB_ENV *dbenv, DB_TXN **tid);

The `DB_ENV->cdsgroup_begin()` method allocates a locker ID in an environment configured for Berkeley DB Concurrent Data Store applications. It copies a pointer to a DB_TXN that uniquely identifies the locker ID into the memory to which tid refers. Calling the DB_TXN->commit() method will discard the allocated locker ID.

See Berkeley DB Concurrent Data Store applications for more information about when this is required.

This method may not be called on a sliced database.

The `DB_ENV->cdsgroup_begin()` method may be called at any time during the life of the application.

The `DB_ENV->cdsgroup_begin()` method returns a non-zero error value on failure and 0 on success.

### Errors

The `DB_ENV->cdsgroup_begin()` method may fail and return one of the following non-zero errors:

#### EINVAL

If this method is called on a sliced database; or if an invalid flag value or parameter was specified.

#### ENOMEM

The maximum number of lockers has been reached.

### Class

DB_ENV, DB_TXN

### See Also

Transaction Subsystem and Related Methods

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