On Wed, Jul 23, 2003 at 03:29:03PM -0400, Glenn Fowler wrote:
>
> On Wed, 23 Jul 2003 12:14:36 -0700 David S. Miller wrote:
> > I missed the reason why you can't use pipes and bash
> > is able to, what is it?
>
> we have some applications, ksh included, with semantics that require
> stdin be read at most one line at a time; an inefficient implementation
> of this does 1 byte read()s until newline is read; an efficient
> implementation does a peek read (without advancing the read/seek offset),
> determines how many chars to read up to and including the newline,
> and then read()s that much
>
> linux has ioctl(I_PEEK) for stream devices and recv() for sockets,
> and neither of these work on pipes; if there is a linux alternative
> for pipes then we'd be glad to use it
>
> we switched from pipe() to socketpair() to take advantage of the linux
> recv() peek read
Perhaps you'd rather code a patch adding peek functionality
for pipes.
-- ________________________________________________________________ J.W. Schultz Pegasystems Technologies email address: jw@pegasys.wsRemember Cernan and Schmitt - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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