Sets the processing instruction (PI) handler function for the XML parser parser.
A processing instruction has the following format:
You can put PHP code into such a tag, but be aware of one limitation: in
an XML PI, the PI end tag (
?>) can not be quoted,
so this character sequence should not appear in the PHP code you embed
with PIs in XML documents.If it does, the rest of the PHP code, as well
as the "real" PI end tag, will be treated as character data.
handler is a string containing the name of a function that must exist when xml_parse() is called for parser.
The function named by handler must accept three parameters:
parser, is a reference to the XML parser calling the handler.
If a handler function is set to an empty string, or
FALSE, the handler
in question is disabled.
Instead of a function name, an array containing an object reference and a method name can also be supplied.