# DbEnv::set_feedback

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    #include <db_cxx.h>

    int
    DbEnv::set_feedback(
        void (*db_feedback_fcn)(DbEnv *, int opcode, int pct));

# Description

Some operations performed by the Berkeley DB library can take non-trivial amounts of time. The DbEnv::set_feedback method can be used by applications to monitor progress within these operations.

When an operation is likely to take a long time, Berkeley DB will call the specified callback method. This method must be declared with three arguments: the first will be a reference to the enclosing environment, the second a flag value, and the third the percent of the operation that has been completed, specified as an integer value between 0 and 100. It is up to the callback method to display this information in an appropriate manner.

The opcode argument may take on any of the following values:

DB_RECOVER
  The environment is being recovered.

The DbEnv::set_feedback interface may be used to configure Berkeley DB at any time during the life of the application.

The DbEnv::set_feedback 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.

# Class

DbEnv

# See Also

DbEnv::close, DbEnv::err, DbEnv::errx DbEnv::open, DbEnv::remove, DbEnv::set_alloc, DbEnv::set_cachesize, DbEnv::set_data_dir, DbEnv::set_errcall, DbEnv::set_errfile, DbEnv::set_error_stream, DbEnv::set_errpfx, DbEnv::set_feedback, DbEnv::set_flags, DbEnv::set_paniccall, DbEnv::set_recovery_init, DbEnv::set_rpc_server, DbEnv::set_shm_key, DbEnv::set_tas_spins, DbEnv::set_tmp_dir, DbEnv::set_timeout, DbEnv::set_verbose, DbEnv::strerror and DbEnv::version.`

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