Set RDF statement callback handler: Raptor RDF Syntax Library Manual

## Set RDF statement callback handler

The main reason to parse a syntax is to get RDF triples returned and these are return by a user-defined handler function which is called with parameters of a user data pointer and a raptor statement, which includes the triple terms plus the optional named graph term. The handler is set with `raptor_parser_set_statement_handler()` as follows:

      void
      statement_handler(void* user_data, const raptor_statement* statement)
      {
        /* do something with the statement */
      }

      raptor_parser_set_statement_handler(rdf_parser, user_data, statements_handler);

Setting a stateemnt handler function is optional since parsing without returning statements is a valid use, such as when parsing in order to validate a syntax.