Before continuing, it is useful to spend a few moments on exception handling in DB with the C++ API.

By default, most DB methods throw DbException in the event of a serious error. However, be aware that DbException does not inherit from std::exception so your try blocks should catch both types of exceptions. For example:

#include <db_cxx.h>
    ...
try 
{
    // DB and other code goes here
}
catch(DbException &e)
{
  // DB error handling goes here
}
catch(std::exception &e)
{
    // All other error handling goes here
} 

You can obtain the DB error number for a DbException by using DbException::get_errno(). You can also obtain the informational message associated with that error number using DbException::what().

If for some reason you do not want to manage DbException objects in your try blocks, you can configure DB to suppress them by setting DB_CXX_NO_EXCEPTIONS for your database and environment handles. In this event, you must manage your DB error conditions using the integer value returned by all DB methods. Be aware that this manual assumes that you want to manage your error conditions using DbException objects. For information on managing error conditions using the integer return values, see Getting Started with Berkeley DB for C.