#include <db_cxx.h> int DbEnv::log_printf(DB_TXN *txnid, const char *fmt, ...);
         The DbEnv::log_printf() method appends an informational message to
         the Berkeley DB database environment log files.
    
         The DbEnv::log_printf() method allows applications to include
         information in the database environment log files, for later review
         using the db_printlog
         utility.  This method is intended for debugging and performance
         tuning.
    
         The DbEnv::log_printf() 
            
            
                method either returns a non-zero error value or throws an
                exception that encapsulates a non-zero error value on
                failure, and returns 0 on success.
            
        
    
If the logged message refers to an application-specified transaction, the txnid parameter is a transaction handle returned from DbEnv::txn_begin(); otherwise NULL.
                         The DbEnv::log_printf() 
            
            
                method may fail and throw a DbException 
                exception, encapsulating one of the following non-zero errors, or return one
                of the following non-zero errors: