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c++tcprecv

What to expect when processing TCP data

I am using a POSIX OS (vxWorks) and want to understand how to process TCP data. I understand in UDP everything is really up to you and TCP is a lot more managed underneath.

Suppose a remote socket I am connected to promises to send me JSON data. The documentation simply says, once established, we will send you JSON data.

Using the function recv on the TCP socket, and assuming I give it a buffer of an extreme size, should I expect that I would always get perfectly assembled JSON data even though the message may be sent in multiple chunks on the interface layer, or do I need to essentially parse each buffer of data I received until I think I have a fully formed JSON message?

Solution

  • TCP has no idea about application messages. You need to implement the protocol layered on top of TCP to find message boundaries, if your protocol has one.