Unix socket, SOCK_SEQPACKET vs SOCK_DGRAM

Question

It seems there\'s atleast 3 different local/unix socket types (AF_UNIX) , SOCK_STREAM, SOCK_DGRAM and SOCK_SEQPACKET.

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Answer 1

SOCK_SEQPACKET gives you the guarantees of SOCK_STREAM (i.e., preservation of ordering, guaranteed delivery, no duplication), but with delineated packet boundaries just like SOCK_DGRAM. So, basically it's a mix of the two protocol types.

In the TCP/IP-family, SCTP implements both SOCK_STREAM (TCP-like) and SOCK_SEQPACKET. Unfortunately it is not stock-available on Windows.