Function xmlAddDocEntity 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn xmlAddDocEntity(
    doc: *mut _xmlDoc,
    name: *const xmlChar,
    type_: c_int,
    ExternalID: *const xmlChar,
    SystemID: *const xmlChar,
    content: *const xmlChar,
) -> *mut _xmlEntity

Add an entity declaration to a document’s internal subset (upstream entities.c xmlAddDocEntity): if the document has no internal subset one is created.

UPSTREAM-PARITY

xmlEntityPtr xmlAddDocEntity(xmlDocPtr doc, const xmlChar *name, int type,
                             const xmlChar *ExternalID, const xmlChar *SystemID,
                             const xmlChar *content);