Function notmuch_sys::notmuch_message_add_property

pub unsafe extern fn notmuch_message_add_property(message: *mut notmuch_message_t,
                                                  key: *const c_char,
                                                  value: *const c_char)
                                                  -> notmuch_status_t

Add a (key,value) pair to a message

@returns - notmuch_status_t::ILLEGAL_ARGUMENT: key may not contain an '=' character. - notmuch_status_t::NULL_POINTER: Neither key nor value may be NULL. - notmuch_status_t::SUCCESS: No error occured. @since libnotmuch 4.4 (notmuch 0.23)