Skip site navigation (1)Skip section navigation (2)
Date:      11 May 1997 17:54:37 +0100
From:      Andrew Gierth <andrew@erlenstar.demon.co.uk>
To:        "John S. Dyson" <toor@dyson.iquest.net>
Cc:        freebsd-hackers@freebsd.org
Subject:   Re: socketpair()
Message-ID:  <87rafene42.fsf@erlenstar.demon.co.uk>
In-Reply-To: "John S. Dyson"'s message of Sun, 11 May 1997 10:55:47 -0500 (EST)
References:  <199705111555.KAA08056@dyson.iquest.net>

next in thread | previous in thread | raw e-mail | index | archive | help
>>>>> "John" == John S Dyson <toor@dyson.iquest.net> writes:

 John> I wrote most of our new pipe code -- and I might be a little bit
 John> confused...  I meant to support bidirectional pipes, and it sure
 John> looks like we have them (at least looking at the code.)  Haven't
 John> tested it recently though.

$ cat <&1 >&2 | echo hello >&0
hello
$

Works OK on RELENG-2.2 at least.

As far as I can tell, though, bidirectional pipes are still pretty much
confined to SVR4 (STREAMS pipes) and FreeBSD; most of the other flavours
I've encountered still use unidirectional pipes (at least by default;
some, like HP-UX 10.10, have a switch for it in the kernel parameters).

In other words, having support for bidirectional pipes is nice, but
relying on them will probably get you into trouble.

Is there actually any good reason for having bidirectional pipes, other
than for coping with code ported from SVR4?

-- 
Andrew.



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?87rafene42.fsf>