Function core_invoice_validate 

#[unsafe(no_mangle)]
pub extern "C" fn core_invoice_validate(
    xml: *const c_char,
    profile: *const c_char,
    err: *mut c_char,
    err_len: usize,
) -> c_int

Same as core_invoice_validate_ubl: syntax is the document element (UBL or CII).