A reference to the XML parser to use.
Chunk of data to parse. A document may be parsed piece-wise by calling xml_parse() several times with new data, as long as the is_final parameter is set and TRUE when the last data is parsed.
If set and TRUE, data is the last piece of data sent in this parse.
When the XML document is parsed, the handlers for the configured events are called as many times as necessary, after which this function returns TRUE or FALSE.
TRUE is returned if the parse was successful, FALSE if it was not successful, or if parser does not refer to a valid parser. For unsuccessful parses, error information can be retrieved with xml_get_error_code(), xml_error_string(), xml_get_current_line_number(), xml_get_current_column_number() and xml_get_current_byte_index().