#include <db_cxx.h> void Db::set_errpfx(const char *errpfx);
Set the prefix string that appears before error messages issued by Berkeley DB.
         The Db::set_errpfx() and 
         DbEnv::set_errpfx() 
         methods do not copy the memory to which the errpfx parameter refers; rather, they maintain
         a reference to it.  Although this allows applications to modify the
         error message prefix at any time (without repeatedly calling the
         interfaces), it means the memory must be maintained until the handle
         is closed.
    
         For Db  handles opened
         inside of Berkeley DB environments, calling the Db::set_errpfx()
         method affects the entire environment and is equivalent to calling the
         DbEnv::set_errpfx() 
         method.
    
         The Db::set_errpfx() method configures operations performed using the
         specified Db  handle, not
         all operations performed on the underlying database.
    
         The Db::set_errpfx() method may be called at any time during the life
         of the application.