How to read a fix-sized packet using boost asio?

Question

I am doing a synchronous read/write using boost-asio. The data is coming in binary format, without boundary, the length information is encoded in the packet

Answer 1

TCP is a stream-based protocol. This means that whatever you read is just a stream of bytes. Let's consider an example: you have a message of a fixed size and you send it over TCP. How can the program at the other end read the entire message? there are two ways, one is to surround you message with control chracters (e.g. STX at start and ETX at end). At the start, the program would discard any chars before STX, then read any other chars into the message buffer until ETX is encountered.

Another way is to encode the message length in a fixed-size header (which apparently is your case). So the best thing you can do is figure out a way to read the message length, parse it and read the remaining bytes accordingly.