Date: Sat, 13 Aug 2005 21:06:35 -0500 From: Bob Willcox <bob@immure.com> To: Colin Percival <cperciva@freebsd.org> Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/usr.sbin/portsnap/portsnap portsnap.sh Message-ID: <20050814020635.GA19321@luke.immure.com> In-Reply-To: <42FE6A67.6000208@freebsd.org> References: <200508132128.j7DLShWb080387@repoman.freebsd.org> <42FE6A67.6000208@freebsd.org>
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On Sat, Aug 13, 2005 at 02:47:19PM -0700, Colin Percival wrote:
> Colin Percival wrote:
> > This bug was caused by the astonishing interaction of "return" and
> > pipelines; in the following code, the "return" does not exit the
> > function, but instead exits the subshell which was spawned for the last
> > element of the pipeline; consequently, the output produced is "foo".
> >
> > foo() {
> > echo bar | while read baz; do
> > if [ ${baz} = "bar" ]; then
> > return 1
> > fi
> > done
> >
> > echo foo
> > }
>
> For what it's worth, I don't know if the behaviour of our sh(1) is correct
> here. IEEE 1003.1, 2004 Ed. says
>
> "The return utility shall cause the shell to stop executing the current function
> or dot script. If the shell is not currently executing a function or dot script,
> the results are unspecified."
>
> and I don't see any mention of not returning from a function just because we
> happen to be inside a subshell.
I tried this on a some different shells. Turns out that bash & pdksh
behave similar to the FreeBSD shell, but with ksh93 the return exits the
function. So maybe ksh93 is the only one working correctly--or it's the
only one that's broke.
Bob
>
> Colin Percival
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--
Bob Willcox The early bird who catches the worm works for someone
bob@immure.com who comes in late and owns the worm farm.
Austin, TX -- Travis McGee
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