Date: Mon, 1 Aug 2016 00:01:51 -0600 From: Warner Losh <imp@bsdimp.com> To: Bruce Evans <brde@optusnet.com.au> Cc: Jilles Tjoelker <jilles@stack.nl>, Alexey Dokuchaev <danfe@freebsd.org>, src-committers <src-committers@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org> Subject: Re: svn commit: r303586 - head/bin/sh Message-ID: <CANCZdfqVs8FPV3%2BpobVhEOHUrgZb5ahyFh2MzLoQ6HNdnwy8gw@mail.gmail.com> In-Reply-To: <20160801154048.K884@besplex.bde.org> References: <201607311311.u6VDBYr8066638@repo.freebsd.org> <20160731134316.GB85936@FreeBSD.org> <20160731201614.GA58505@stack.nl> <CANCZdfqzQO5f_MSCj9pZ63qZO5cSMy6ym9%2BkhVkZ8pVuLXUyEg@mail.gmail.com> <20160801154048.K884@besplex.bde.org>
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On Sun, Jul 31, 2016 at 11:51 PM, Bruce Evans <brde@optusnet.com.au> wrote: > On Sun, 31 Jul 2016, Warner Losh wrote: > >> On Sun, Jul 31, 2016 at 2:16 PM, Jilles Tjoelker <jilles@stack.nl> wrote: >>> >>> On Sun, Jul 31, 2016 at 01:43:16PM +0000, Alexey Dokuchaev wrote: >>>> >>>> On Sun, Jul 31, 2016 at 01:11:34PM +0000, Jilles Tjoelker wrote: >>>>> >>>>> New Revision: 303586 >>>>> URL: https://svnweb.freebsd.org/changeset/base/303586 >>> >>> >>>>> Log: >>>>> sh: Fix a clang warning. >>> >>> >>>>> Submitted by: bdrewery >>> >>> >>>>> Modified: >>>>> head/bin/sh/expand.c >>> >>> >>>>> Modified: head/bin/sh/expand.c >>>>> >>>>> ============================================================================== >>>>> --- head/bin/sh/expand.c Sun Jul 31 12:59:10 2016 (r303585) >>>>> +++ head/bin/sh/expand.c Sun Jul 31 13:11:34 2016 (r303586) >>>>> @@ -473,7 +473,8 @@ expbackq(union node *cmd, int quoted, in >>>>> if (--in.nleft < 0) { >>>>> if (in.fd < 0) >>>>> break; >>>>> - while ((i = read(in.fd, buf, sizeof buf)) < 0 && >>>>> errno == EINTR); >>>>> + while ((i = read(in.fd, buf, sizeof buf)) < 0 && >>>>> errno == EINTR) >>>>> + ; >>> >>> >>>> `continue;' would be even better; some tools might barf at stray >>>> semicolon. >>> >>> >>> Both continue; and ; (the latter with and without comment) occur in the >>> source tree many times. I don't really like a continue that does nothing >>> because it is at the end of a loop, so I prefer to make this whitespace >>> change only (there are two more instances in bin/sh). I think a sole >>> semicolon on a line is conspicuous enough that nothing additional is >>> required. >> >> >> For humans, yes. For picky tools that warn about strange constructs, no. >> Clang may be happy, but there's many other tools that expect you to >> declare >> an 'empty' while loop with continue. This tradition has dated back to >> at least the >> late 80's... > > > Buggy tools. I thought that programmers used the stand-alone semicolon > since that is shorter and clearer. It cannot be on the same line though. > The stand-alone semicolon is bad if it is misformatted. 'while(foo());' > is shorter and unclearer. A C parser must ignore whitespace, so you > need a tool like indent that sort of understands whitespace to disallow > while(foo()); but accept 'while (foo())\n\t;'. It is not far from full > indent(1) and insisting on the correct number of \t's before the semicolon. A C parser doesn't completely ignore the whitespace if it doesn't warn in both cases... Warner
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