Re: [exim-dev] Exim 4.75 RC2 uploaded

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Autor: Heiko Schlichting
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A: exim-dev
Assumpte: Re: [exim-dev] Exim 4.75 RC2 uploaded
> On 2011-02-22 at 18:31 +0100, Heiko Schlichting wrote:
> > > I have uploaded Exim 4.75 RC2 to:
> > >     ftp://ftp.exim.org/pub/exim/exim4/test/

> >
> > While building 4.75 RC2 on IRIX, we stumbled over two problems:
> >
> > - scripts/lookups-Makefile uses the $(command) syntax for command
> > substitution, which isn't supported by the traditional Bourne shell
> > implementations used by most commercial Unix systems. It would be
> > more portable to use the `command` syntax instead.
>
> Does IRIX ship with a different shell which is POSIX compliant? ksh?


/bin/sh is ksh on IRIX but in compatibility mode. In the mentioned case it
is easy to use `command` instead of $(command) which would be more
portable.

But if you want to use POSIX features it is possible by setting environment
variable _XPG to 1. From sh(1):

| COMPATIBILITY ISSUES
|      To retain some backward compatibility to the Bourne shell, certain Korn
|      shell features are controlled by how the shell is invoked and/or the
|      current value of the environment variable _XPG.
| 
|      When the shell is invoked as "sh", the following features are performed
|      only when the current value of the _XPG variable is equal to 1 (one):
| 
|           - command substitution of the form "$( command )"
|           [...]


> I can change the invocation, but we're already accepting that sometimes
> we just need to ask for a POSIX environment instead of working with
> whatever's there by default (see the Solaris bit at the top of that same
> script), so it'd be nice to adjust things to work with syntax
> standardised in 1992, now that it's 2011.


Although the last IRIX version is from 2006, it is possible to use POSIX
features by setting _XPG to 1. Due to overdoing compatibility this is not
the default if invoked as "sh".

Heiko

Heiko Schlichting                Freie Universität Berlin
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