Function xmlHashAdd 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn xmlHashAdd(
    hash: *mut c_void,
    name: *const xmlChar,
    userdata: *mut c_void,
) -> c_int

Add a hash table entry.

UPSTREAM-PARITY

int xmlHashAdd(xmlHashTable *hash, const xmlChar *name, void *userdata);

Returns 1 on success, 0 if an entry exists and -1 in case of error.