protocol buffers : no notation for fixed size buffers?

Question

Since I am not getting an answer on this question I gotta prototype and check myself, as my dataset headers need to be fixed size, I need fixed size strings. So, is it possible to specify fixed size strings or byte arrays in protocol buffers ? It is not readily apparent here, and I kinda feel bad about forcing fixed size strings into the header message. --i.e, std::string('\0', 128);

If not I'd rather use a #pragma pack(1) struct header {...};'

edit

Question indirectly answered here. Will answer and except

Answer 1

protobuf does not have such a concept in the protocol, nor in the .proto schema language. In strings and blobs, the data is always technically variable length using a length prefix (which itself uses varint encoding, so even the length is variable length).

Of course, if you only ever store data of a particular length, then it will line up. Note also that since strings in protobuf are unicode using UTF-8 encoding, the length of the encoded data is not as simple as the number of characters (unless you are using only ASCII characters).