#include <db.h>

DB->set_feedback(DB *,
    void (*db_feedback_fcn)(DB *dbp, int opcode, int percent));  

Some operations performed by the Berkeley DB library can take non-trivial amounts of time. The DB->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 function with progress information.

It is up to the callback function to display this information in an appropriate manner.

The DB->set_feedback() method may be called at any time during the life of the application.

The DB->set_feedback() method returns a non-zero error value on failure and 0 on success.


Berkeley DB is not re-entrant. Callback functions should not attempt to make library calls (for example, to release locks or close open handles). Re-entering Berkeley DB is not guaranteed to work correctly, and the results are undefined.



The db_feedback_fcn parameter is the application-specified feedback function called to report Berkeley DB operation progress. The callback function must take three parameters:

  • dbp

    The dbp parameter is a reference to the enclosing database.

  • opcode

    The opcode parameter is an operation code. The opcode parameter may take on any of the following values:


      The underlying database is being upgraded.


      The underlying database is being verified.

  • percent

    The percent parameter is the percent of the operation that has been completed, specified as an integer value between 0 and 100.



See Also

Database and Related Methods