Re: grep-2.9.69-f91c on OSF/1

[Stefano Lattarini]

Hi Eric.

On Friday 11 November 2011, Eric Blake wrote:
> [adding autoconf]
> 
> On 11/11/2011 01:38 PM, Bruno Haible wrote:
> 
> > The syntax "export VAR=VALUE" is not guaranteed by this shell.
> > Either write "env VAR=VALUE ...", or "VAR=VALUE; export VAR; ..."
> 
> > 
> > Strangely enough, this portability problem of the 'export' built-in
> > is well-known, but not mentioned in the Autoconf manual
> > <http://www.gnu.org/software/autoconf/manual/html_node/Limitations-of-Builtins.html>.
> 
> Hmm, I could have sworn it was in there, but you appear to be right.
> I'll be committing this soon.
> 
> diff --git i/ChangeLog w/ChangeLog
> index e51f7d7..72b1dbc 100644
> --- i/ChangeLog
> +++ w/ChangeLog
> @@ -1,3 +1,10 @@
> +2011-11-11  Eric Blake  <address@hidden>
> +
> +     doc: mention export portability hint
> +     * doc/autoconf.texi (Limitations of Builtins) <export>: Document
> +     export limitation.
> +     Suggested by Bruno Haible.
> +
>  2011-10-21  Stefano Lattarini  <address@hidden>
> 
>       fortran: define $GFC to "yes" if $FC is a GNU compiler
> diff --git i/doc/autoconf.texi w/doc/autoconf.texi
> index b6dc67b..417c432 100644
> --- i/doc/autoconf.texi
> +++ w/doc/autoconf.texi
> @@ -17642,6 +17642,20 @@ Limitations of Builtins
>  foo=
>  @end example
> 
> +Posix requires @command{export} to honor assignments made as arguments,
> +but older shells did not support this.  Portable scripts should separate
> +assignments and exports into different statements (it does not matter if
> +the export comes before or after the assignment).
> +
> address@hidden
> +$ @kbd{bash -c 'export foo=bar; echo $foo'}
> +bar
> +$ @kbd{/bin/sh -c 'export foo=bar; echo $foo'}
> +/bin/sh: foo=bar: is not an identifier
> +$ @kbd{/bin/sh -c 'export foo; foo=bar; echo $foo'}
> +bar
> address@hidden example
> +
>
I think it would be worth mentioning explicitly some shells that behave like
this (Solaris 10 /bin/sh does, for example).  For a rationale about why this
should be useful, see:
 <http://lists.gnu.org/archive/html/autoconf-patches/2011-08/msg00007.html>

Regards,
  Stefano