PHP Manual: Create start namespaced element tag

Object-oriented style

public bool XMLWriter::startElementNs(stringnull $prefix, string $name, stringnull $namespace)

Procedural style

bool xmlwriter_start_element_ns(
    XMLWriter $writer,
    stringnull $prefix,
    string $name,
    stringnull $namespace
)

Starts a namespaced element.

writer: Only for procedural calls. The XMLWriter instance that is being modified. This object is returned from a call to xmlwriter_open_uri or xmlwriter_open_memory.
prefix: The namespace prefix. If prefix is null, the namespace will be omitted.
name: The element name.
namespace: The namespace URI. If namespace is null, the namespace declaration will be omitted.

Returns true on success or false on failure.

Version	Description
8.0.0	`writer` expects an XMLWriter instance now; previously, a resource was expected.

XMLWriter::startElementNs