The libecpg library primarily contains "hidden" functions that are used to implement the functionality expressed by the embedded SQL commands. But there are some functions that can usefully be called directly. Note that this makes your code unportable.
     ECPGdebug(int on, FILE
     *stream) turns on debug
     logging if called with the first argument non-zero. Debug logging
     is done on stream. Most
     SQL statement log their arguments and results.
    
     The most important function, ECPGdo, logs
     all SQL statements with both the expanded
     string, i.e. the string with all the input variables inserted,
     and the result from the PostgreSQL
     server. This can be very useful when searching for errors in your
     SQL statements.
    
     ECPGstatus() This method returns true if we
     are connected to a database and false if not.