standards/66357: make POSIX conformance problem ('sh -e' & '+'
command-line flag)
Harti Brandt
novo at cs.tu-berlin.de
Tue May 25 08:50:50 PDT 2004
The following reply was made to PR standards/66357; it has been noted by GNATS.
From: Harti Brandt <novo at cs.tu-berlin.de>
To: "Mark D. Baushke" <mdb at juniper.net>
Cc: FreeBSD-gnats-submit at FreeBSD.ORG
Subject: Re: standards/66357: make POSIX conformance problem ('sh -e' & '+'
command-line flag)
Date: Tue, 25 May 2004 17:43:07 +0200 (MET DST)
[CC's removed]
[Sorry for the delay, I just discovered that this is still in my mailbox].
On Mon, 10 May 2004, Mark D. Baushke wrote:
> Harti Brandt <novo at 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'm currently moving jobs and have no access to my link-list, but
you should be able to find the mailing lists on the opengroup web page.
I know that they are not easy to find - watch for Austing Group.
>
> > 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.
The big problem is things like
HDRS=a.h b.h c.h
install:
for i in $(HDRS) ; do cp $$i /dest ; done
If one of the cp's fail, make should abort. That is possible only when
doing sh -e. Otherwise a failing cp will just go by unnoticed.
What kind of fragility did you see?
> 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...
There is a long way to get our make POSIX compliant. I think this should
be done very careful step by step. I have already one change in the pipe
for three months now (standards/57295) - the problem is not to break large
numbers of ports, so I really don't want to comnment on the %POSIX stuff
atm. Perhaps it would be best to open another PR for this so we don't mix
different things.
> I look forward to learning what FreeBSD will do.
I'll try to move our make in the POSIX direction, but, as I said this will
take some time because make is a very central utility to the system.
Let me first get the above PR finished, the I will move on to this one.
harti
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