[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Proposed doc updates

From: Ralf Wildenhues
Subject: Re: Proposed doc updates
Date: Wed, 26 Jan 2005 18:41:39 +0100
User-agent: Mutt/1.4.1i

* Noah Misch wrote on Wed, Jan 26, 2005 at 03:07:23AM CET:
> On Mon, Jan 24, 2005 at 06:22:04AM -0700, Eric Blake wrote:
> > 2005-01-24  Eric Blake  <address@hidden>
> > 
> >     * doc/autoconf.texi (Portable Shell): Autoconf uses functions.
> _AS_SHELL_FN_SPY tries trivial shell functions in a protected subshell so we 
> can
> raise a warning asking the user to report his or her function-ignorant shell 
> to
> address@hidden  Is that not the only use?

This should also check whether the positional parameters of the script
are restored after function return -- not doing this will most likely be
a killer for any kind of serious shell function usage.

> > +Ash checks that a command exists and is executable before performing
> > +redirections.  Therefore, a warning will escape to stderr.  The portable
> > +way to check for a command's existance is to redirect stderr of the
> > +subshell performing the check.
> > +
> > address@hidden
> > +$ @kbd{nonexistant 2> /dev/null}
> > address@hidden: not found
> > +$ @kbd{(nonexistant) 2> /dev/null}
> { nonexistant; } 2>/dev/null also works, at least on the version of Ash I have
> handy.  It has the benefit of not forking.

This is nice.  A couple of Bourne shell derivatives I tested also work
with it -- they fork, but that is not a big problem (they also output
an error with
  nonexistent 2> /dev/null
(please   ^ mind the e here).

Does anybody know a shell which still outputs anything with this?
Libtool could benefit from it (as could some autoconf stuff).


reply via email to

[Prev in Thread] Current Thread [Next in Thread]