1 // This is an example of how to handle 'union' style messages 2 // with nanopb, without allocating memory for all the message types. 3 // 4 // There is no official type in Protocol Buffers for describing unions, 5 // but they are commonly implemented by filling out exactly one of 6 // several optional fields. 7 8 message MsgType1 9 { 10 required int32 value = 1; 11 } 12 13 message MsgType2 14 { 15 required bool value = 1; 16 } 17 18 message MsgType3 19 { 20 required int32 value1 = 1; 21 required int32 value2 = 2; 22 } 23 24 message UnionMessage 25 { 26 optional MsgType1 msg1 = 1; 27 optional MsgType2 msg2 = 2; 28 optional MsgType3 msg3 = 3; 29 } 30 31
