XML Parser Functions
PHP Manual

xml_set_start_namespace_decl_handler

Set up start namespace declaration handler

Description

true xml_set_start_namespace_decl_handler(XMLParser $parser, callable $handler)

Set a handler to be called when a namespace is declared. Namespace declarations occur inside start tags. But the namespace declaration start handler is called before the start tag handler for each namespace declared in that start tag.

Parameters

parser

The XML parser.

handler

If null is passed, the handler is reset to its default state.

Warning

An empty string will also reset the handler, however this is deprecated as of PHP 8.4.0.

If handler is a callable, the callable is set as the handler.

If handler is a string, it can be the name of a method of an object set with xml_set_object.

Warning

This is deprecated as of PHP 8.4.0.

Warning

As of PHP 8.4.0, the callable is checked to be valid while setting the handler, not when it is called. This means that xml_set_object must be called prior to setting a method string as the callback. However, as this behaviour is also deprecated as of PHP 8.4.0, using a proper callable for the method is recommended instead.

The signature of the handler must be:

void handler(XMLParser $parser, stringfalse $prefix, string $uri)
parser
The XML parser calling the handler.
prefix
The prefix is a string used to reference the namespace within an XML object. false if no prefix exists.
uri
Uniform Resource Identifier (URI) of namespace.

Return Values

Always returns true.

Changelog

Version Description
8.4.0 Passing a non-callable string to handler is now deprecated, use a proper callable for methods, or null to reset the handler.
8.4.0 The validity of handler as a callable is now checked when setting the handler instead of checking when calling it.
8.0.0 parser expects an XMLParser instance now; previously, a valid xml resource was expected.

See Also

  • xml_set_end_namespace_decl_handler