Re: [PATCH] Remove more gcc extension usage.

From: Jan-Benedict Glaw <jbglaw@lug-owl.de>
Date: Jul 9, 2006, 07:31 UTC
Message-ID: <20060709073155.GP22573@lug-owl.de>
In-Reply-To: <20060708190327.GA17763@spearce.org>

On Sat, 2006-07-08 15:03:27 -0400, Shawn Pearce <spearce@spearce.org> wrote:

Show 18 quoted lines

> Junio C Hamano <junkio@cox.net> wrote:
> > Shawn Pearce <spearce@spearce.org> writes:
> > 
> > > Removing these last remaining extension uses allows GIT to compile
> > > with the Sun C compiler rather then gcc.  This can be handy when
> > > you are trying to compile GIT on a Solaris system that seems to
> > > have a total lack of GNU utilities.
> > 
> > Two points.
> > 
> >  - Aren't the constructs you ripped out not GCC extension,
> >    rather proper ISO C99?
> 
> Hmm.  I'm not sure actually.  I don't do much C hacking these days
> so I haven't kept current with what C99 has and doesn't.  I just
> know that these small changes made the core plumbing build and run
> fine on Solaris with only GNU make being present.  I didn't even
> attempt to use the higher level Poreclainish shell script commands.

Yes, that's valid C99. So Sun ships a compiler conforming to old standards only, or which is configured to do so.

> Monday I'll look to see if there's an option that can be given to
> the Solaris compiler to make it accept these constructs.  Maybe a
> simple CFLAGS change in my config.mak would resolve what this patch
> was trying to do.

Thanks.

Show 11 quoted lines

> >  - Our Makefile is pretty GNU already.  I think people have
> >    pointed out and ripped out bashisms from our shell scripts,
> >    but I would not be surprised if the default Sun /bin/sh does
> >    not understand POSIXy features some of them use.
> 
> I realize that.  Asking someone to compile GNU make in their home
> directory before they build GIT to their home directory isn't a
> big deal (took me all of 30 seconds to download the latest and
> ./configure&&make install it).  Asking someone to download and
> compile binutils and gcc because their local site manager won't
> install them for you is another matter entirely...

AFAIK, relying on the '#!/bin/sh' thing is, from the POSIX point of view, just plain wrong. IIRC, the '#!' thing even doesn't need to be implemented! POSIX tells you to call scripts with their interpreters, for a reason. /bin/sh needn't be POSIX compliant, but the first shell found in the $PATH has to. So for what it's worth, shell scripts should be called like `sh foo.sh', and if we narrow to expect the `#!' to work, we'd better call it like `#!/usr/bin/env sh' to get the $PATH `sh' and not /bin/sh .

MfG, JBG

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