# libxml（内置 默认开启） 这些函数/常量从PHP 5.1.0开始可用，以下核心扩展依赖于此libxml扩展：[DOM](https://www.php.net/manual/en/book.dom.php)，[libxml](https://www.php.net/manual/en/book.libxml.php)，[SimpleXML](https://www.php.net/manual/en/book.simplexml.php)，[SOAP](https://www.php.net/manual/en/book.soap.php)，[WDDX](https://www.php.net/manual/en/book.wddx.php)，[XSL](https://www.php.net/manual/en/book.xsl.php)，[XML](https://www.php.net/manual/en/book.xml.php)，[XMLReader](https://www.php.net/manual/en/book.xmlreader.php)，[XMLRPC](https://www.php.net/manual/en/book.xmlrpc.php)和[XMLWriter](https://www.php.net/manual/en/book.xmlwriter.php) - [预定义常量](https://www.php.net/manual/en/libxml.constants.php) - [libXMLError](https://www.php.net/manual/en/class.libxmlerror.php)— libXMLError类 - [libxml函数](https://www.php.net/manual/en/ref.libxml.php) - [libxml\_clear\_errors](https://www.php.net/manual/en/function.libxml-clear-errors.php)—清除libxml错误缓冲区 - [libxml\_disable\_entity\_loader](https://www.php.net/manual/en/function.libxml-disable-entity-loader.php)—禁用加载外部实体的功能 - [libxml\_get\_errors](https://www.php.net/manual/en/function.libxml-get-errors.php)—检索错误数组 - [libxml\_get\_last\_error](https://www.php.net/manual/en/function.libxml-get-last-error.php)—从libxml检索最后一个错误 - [libxml\_set\_external\_entity\_loader](https://www.php.net/manual/en/function.libxml-set-external-entity-loader.php)—更改默认的外部实体加载器 - [libxml\_set\_streams\_context](https://www.php.net/manual/en/function.libxml-set-streams-context.php)—设置下一个libxml文档加载或写入的流上下文 - [libxml\_use\_internal\_errors](https://www.php.net/manual/en/function.libxml-use-internal-errors.php)—禁用libxml错误，并允许用户根据需要获取错误信息