libxml_use_internal_errors
Introduction
XML Manipulation
PHP Manual

# qtdom

- Introduction
- Installing/Configuring
  - Installation
  - Runtime Configuration
  - Resource Types
- Predefined Constants
- qtdom Functions
  - qdom_error — Returns the error string from the last QDOM operation or FALSE if no errors occurred
  - qdom_tree — Creates a tree of an XML string

libxml_use_internal_errors
Introduction
XML Manipulation
PHP Manual