[TUHS] sockets (was Re: First appearance of named pipes)

[Tony Finch]

Norman Wilson <norman at oclsc.org> wrote:
>
> I wish POSIX and Linux and the BSDs would catch up; that
> was only 30 years ago.

After sockets were added to BSD, pipe() was implemented using them. But it
was a slightly different implementation than socketpair().

e.g.
https://minnie.tuhs.org/cgi-bin/utree.pl?file=4.2BSD/usr/src/sys/sys/uipc_syscalls.c

and the amusing comment at the top of
https://minnie.tuhs.org/cgi-bin/utree.pl?file=4.2BSD/usr/src/sys/sys/uipc_pipe.c

But the socket-backed pipes weren't bidirectional even though they could
have been - see this fix in FreeBSD
https://svnweb.freebsd.org/base/head/sys/kern/uipc_syscalls.c?r1=12843&r2=13146

Which did not last long because socket-backed pipe were soon replaced
with a new (bidirectional) implementation
https://svnweb.freebsd.org/base/head/sys/kern/sys_pipe.c?view=log&log_pagestart=200#rev13675

Tony.
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