When using a raw TCP socket, there is a need for doing message framing, as explained here, either with a length prefix, or with delimiters.
I came accross the "SOCK_SEQPACKET" socket option today, which could apparently do the message framing almost transparently.
What is the availability of "SOCK_SEQPACKET" amongst platforms and OSes at the moment? (Windows, OSX, Linux, IOS, Android...)
I you uses SOCK_SEQPACKET of AF_INET, this way:
socket(AF_INET, SOCK_SEQPACKET, 0);
You won't get a TCP socket. The socket will be a SCTP socket, if your platform supports it.
SCTP is not yet widely used. Latest Linux versions supports it (if SCTP is enabled).
There are some libraries also for Windows.
SCTP is still not available on Mac OS X (El Captain). There is a 3rd party open-source kernel extension at https://github.com/sctplab/SCTP_NKE_ElCapitan - But it is unsigned, therefore you have to disable Apple System Integrity Protection.
See e.g. https://apple.stackexchange.com/questions/114217/sctp-kernel-extension-for-mavericks
Equally, you cannot use SOCK_SEQPACKET with AF_UNIX on Mac OS X too.