For protocols, you might be worrying about the bytes and use a 1 2 4 or 8 byte len, or some complicated variable length integer like ASN.1 or something homegrow

For protocols, you might be worrying about the bytes and use a 1 2 4 or 8 byte len, or some complicated variable length integer like ASN.1 or something homegrown (but actually, with the slower networks, if you have a 2M msg, you'd split it into 64k that fit into your 16-bit length prefixed protocol and stream it), but for the parsed data, probably you'd do size_t or ssize_t, byte[], for portability. The standard parsing API would pass in (buf, buf_len) (or (pos, buf, buf_len), and the standard struct would be (name_len size_t , name Byte *) (where Byte was typedef to unsigned char, so you wouldn't pick up signed char by mistake).