Date: Mon, 10 May 2004 09:20:26 -0700 (PDT)
From: "Mark D. Baushke" <mdb@juniper.net>
To: freebsd-standards@FreeBSD.org
Subject: Re: standards/66357: make POSIX conformance problem ('sh -e' & '+' command-line flag)
Message-ID: <200405101620.i4AGKQ74085412@freefall.freebsd.org>
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The following reply was made to PR standards/66357; it has been noted by GNATS.
From: "Mark D. Baushke" <mdb@juniper.net>
To: harti@FreeBSD.ORG
Cc: FreeBSD-gnats-submit@FreeBSD.ORG,
Paul Eggert <eggert@cs.ucla.edu>,
"Simon J. Gerraty" <sjg@crufty.net>, freebsd-standards@FreeBSD.ORG
Subject: Re: standards/66357: make POSIX conformance problem ('sh -e' & '+' command-line flag)
Date: Mon, 10 May 2004 09:13:08 -0700
Harti Brandt <novo@cs.tu-berlin.de> writes:
> On Fri, 7 May 2004, Mark D. Baushke wrote:
>
> >
> > >Number: 66357
> > >Category: standards
> > >Synopsis: make POSIX conformance problem ('sh -e' & '+' command-line)
...
> > >Description:
> > Background:
> >
> > POSIX 1003.2-1997 states that each makefile command line is processed
> > as if given to system(3) (see URL
> > http://www.opengroup.org/onlinepubs/009695399/utilities/make.html)
> >
> > POSIX 1003.1-2004 (as well as older versions of the standard) states
> > that system() does not use the "sh -e" command to exit immediately if
> > any untested command fails in non-interactive mode. (see URL
> > http://www.opengroup.org/onlinepubs/009695399/functions/system.html)
...
>
> The 'sh -e' servers a purpose if you have a more
> complicated shell line say a loop. Without -e make will
> not stop even if there is an error in an inner command of
> a shell loop, while with -e it will exit. I'd say that not
> using -e is a posix-bug, not a feature and, in fact, there
> has been thoughts on the austin group mailing list to
> review this.
If you have any particular URLs for those austin group
mailing list threads, I would be interested in reading them.
I tried to do a quick google search and did not meet with
success to finding such a discussion.
> I'd think even if we remove the -e in the posix case, we
> must retain it in the non-posix case.
fwiw: I have found the 'sh -e' feature to be fragile and
more likely to do the wrong thing in a complicated action
rule especially across multiple platforms.
I also wonder if you will also have time to consider how to
deal with a .POSIX: setting in a Makefile after sys.mk has
already apparently been read in and processed including a
number of .if defined(%POSIX) macros settings being done
already before the first line of the user's Makefile is
processed...
For example, consider the following Makefile:
.POSIX:
arflags:;@echo ARFLAGS = ${ARFLAGS}, POSIX = ${%POSIX}
the FreeBSD 5.2-RELEASE /usr/share/mk/sys.mk has the conditional:
.if defined(%POSIX)
ARFLAGS ?= -rv
.else
ARFLAGS ?= rl
.endif
but the value that /usr/bin/make will print for ARFLAGS in
this case is
ARFLAGS = rl, POSIX = 1003.2
rather than the correct POSIX value.
It all makes some sense when one understands that sys.mk is
read first, but I suspect that most folks trying to use
.POSIX: may consider it a bug rather than a feature to need
to use '%POSIX=1003.2' as an argument on the 'make' command
line since %POSIX may not be set an an environment variable
in the shell.
I look forward to learning what FreeBSD will do.
Thank you for your consideration of these problems.
-- Mark
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