int xml_set_processing_instruction_handler(int parser, string handler);
Sets the processing instruction (PI) handler function for the XML parser parser. handler is a string containing the name of a function that must exist when xml_parse() is called for parser.
A processing instruction has the following format:
<? target data?>
The function named by handler must accept three parameters:
handler(int parser, string target, string data);
The first parameter, parser, is a reference to the XML parser calling the handler.
The second parameter, target, contains the PI target.
The third parameter, data, contains the PI data.
If a handler function is set to an empty string, or false, the handler in question is disabled.
True is returned if the handler is set up, false if parser is not a parser.
There is currently no support for object/method handlers.