#include <db_cxx.h>
int
DbEnv::set_feedback(void (*db_feedback_fcn)(DbEnv *dbenv, int opcode,
int percent));
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 function with progress information.
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.
It is up to the callback function to display this information in an appropriate manner.
The DbEnv::set_feedback() method configures operations performed
using the specified DbEnv handle.
The DbEnv::set_feedback() method may be called at any time during
the life of the application.
The DbEnv::set_feedback() method returns a non-zero error value on
failure and 0 on success.
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:
dbenv
The dbenv parameter is a reference to the enclosing database environment.
opcode
The opcode parameter is an operation code. The opcode parameter may take on any of the following values:
percent
The percent parameter is the percent of the operation that has been completed, specified as an integer value between 0 and 100.