> Both of those seem (IMHO) like functions you could have in a TCP library. Neither seems (IMHO) like a higher level protocol. It's responding to the last part

> Both of those seem (IMHO) like functions you could have in a TCP library. Neither seems (IMHO) like a higher level protocol. It's responding to the last part. It is a higher level of protocol. In the traditional TCP/IP model, it's in the application level. There are many libraries with an API like you asked, they are just in a higher level. (and TCP_WAITALL is a partial solution, applicable only if you know in advance the exact size of the message you are about to receive)