notation_source
notation_source (name[, doc])
The notation_source function returns a number indicating the origin of the declaration for the notation named name. The return value is one of the integers:
• -1 — notation not declared.
• 0 — notation defaulted.
• 1 — notation declared in declaration subset (private markup) only.
• 2 — notation declared in DTD only.
• 3 — notation declared in both DTD and declaration subset.
The doc argument specifies the identifier of the document tree to query. If omitted or 0, the current document is used.