Berkeley DB: Dbc::dup
Description: Berkeley DB: An embedded database programmatic toolkit.
Keywords: embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,java,C,C++

# Dbc::dup |

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    #include <db_cxx.h>

    int
    Dbc::dup(Dbc **cursorp, u_int32_t flags);

# Description

The Dbc::dup method creates a new cursor that uses the same transaction and locker ID as the original cursor. This is useful when an application is using locking and requires two or more cursors in the same thread of control.

The flags value must be set to 0 or by bitwise inclusively OR'ing together one or more of the following values:

DB_POSITION
  The newly created cursor is initialized to refer to the same position in the database as the original cursor and hold the same locks. If the DB_POSITION flag is not specified, then the created cursor is uninitialized and will behave like a cursor newly created using Db::cursor.

When using the Berkeley DB Concurrent Data Store product, there can be only one active write cursor at a time. For this reason, attempting to duplicate a cursor for which the DB_WRITECURSOR flag was specified during creation will return an error.

If the cursor argument is not yet initialized, the Dbc::dup method either returns EINVAL or throws an exception that encapsulates EINVAL.

Otherwise, the Dbc::dup 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 Dbc::dup method may fail and throw an exception or return a non-zero error for the following conditions:

EINVAL
  An invalid flag value or parameter was specified.

  The cursor argument was created using the DB_WRITECURSOR flag in the Berkeley DB Concurrent Data Store product.

The Dbc::dup 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 Dbc::dup 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.

# Class

Dbc

# See Also

Dbc::close, Dbc::count, Dbc::del, Dbc::dup, Dbc::get, Dbc::pget, and Dbc::put.`

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