# DB_ENV->set_feedback

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    #include <db.h>

    int
    DB_ENV->set_feedback(DB_ENV *,
        void (*db_feedback_fcn)(DB_ENV *, int opcode, int pct));

# Description

Some operations performed by the Berkeley DB library can take non-trivial amounts of time. The DB_ENV->set_feedback function 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 function. This function 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 function 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 DB_ENV->set_feedback interface may be used to configure Berkeley DB at any time during the life of the application.

The DB_ENV->set_feedback function returns a non-zero error value on failure and 0 on success.

# See Also

db_env_create, DB_ENV->close, DB_ENV->err, DB_ENV->errx DB_ENV->open, DB_ENV->remove, DB_ENV->set_alloc, DB_ENV->set_cachesize, DB_ENV->set_data_dir, DB_ENV->set_errcall, DB_ENV->set_errfile, DB_ENV->set_errpfx, DB_ENV->set_feedback, DB_ENV->set_flags, DB_ENV->set_mutexlocks, db_env_set_pageyield, DB_ENV->set_paniccall, db_env_set_panicstate, DB_ENV->set_recovery_init, DB_ENV->set_rpc_server, db_env_set_region_init, DB_ENV->set_shm_key, db_env_set_tas_spins, DB_ENV->set_tmp_dir, DB_ENV->set_verbose, db_strerror and db_version.`

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