Re: [9fans] Pipes on UNIX

[Enrico Weigelt <weigelt@metux.de>]

* Lluís Batlle <viriketo@gmail.com> wrote:

Hi,

although, it's quite OT ...

> I understand from [1] that named pipes are suposed to use the
> filesystem as an "unlimited" buffer for the pipe. 

Actually, not. (at least on Unix)

Pipes are FIFOs with an limited buffer size (ie on linux-2.4 of one 
page=4k, on linux-2.6 IMHO 64k). And pipes are always meant for an 
sequential and continous data flow between reader and writer. Yes, 
there are some deadlock flaws (experienced them by myself ie. w/ 
sun-jdk), but they don't come from a limited buffer, but unclean 
handling of tricky situations (ie too large or asymetric chunks on 
reader vs. writer). You probably can work around them by reading
byte per byte (ugly!).

Maybe you would like to have a look at Unix Domain Sockets.
They support bi-directional transfers, fd passing (at least @ Linux)
and packet transfer. You can control many things using setsockopt(1).

> Or maybe the named pipes were never supposed to use the disk as
> the pipe buffer?

Exactly.

For those things you could simply write an little 9p server ;-)
 

cu
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