# Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

`XML_ERROR_NONE` (integer)
`XML_ERROR_NO_MEMORY` (integer)
`XML_ERROR_SYNTAX` (integer)
`XML_ERROR_NO_ELEMENTS` (integer)
`XML_ERROR_INVALID_TOKEN` (integer)
`XML_ERROR_UNCLOSED_TOKEN` (integer)
`XML_ERROR_PARTIAL_CHAR` (integer)
`XML_ERROR_TAG_MISMATCH` (integer)
`XML_ERROR_DUPLICATE_ATTRIBUTE` (integer)
`XML_ERROR_JUNK_AFTER_DOC_ELEMENT` (integer)
`XML_ERROR_PARAM_ENTITY_REF` (integer)
`XML_ERROR_UNDEFINED_ENTITY` (integer)
`XML_ERROR_RECURSIVE_ENTITY_REF` (integer)
`XML_ERROR_ASYNC_ENTITY` (integer)
`XML_ERROR_BAD_CHAR_REF` (integer)
`XML_ERROR_BINARY_ENTITY_REF` (integer)
`XML_ERROR_ATTRIBUTE_EXTERNAL_ENTITY_REF` (integer)
`XML_ERROR_MISPLACED_XML_PI` (integer)
`XML_ERROR_UNKNOWN_ENCODING` (integer)
`XML_ERROR_INCORRECT_ENCODING` (integer)
`XML_ERROR_UNCLOSED_CDATA_SECTION` (integer)
`XML_ERROR_EXTERNAL_ENTITY_HANDLING` (integer)
`XML_OPTION_CASE_FOLDING` (integer)
`XML_OPTION_TARGET_ENCODING` (integer)
`XML_OPTION_SKIP_TAGSTART` (integer)
`XML_OPTION_SKIP_WHITE` (integer)
`XML_SAX_IMPL` (string)
  Holds the SAX implementation method. Can be libxml or expat.