Re: recursive make variables coming to POSIX

[Eric Blake]

On 12/02/2010 12:10 PM, Ralf Wildenhues wrote:
> I'm not sure if it was mentioned before in the discussion, but
> portability-wise, there is a difference between one level of recursion
> and arbitrary many.  IIRC then IRIX make only supported one level, i.e.,
>   $(var1$(var2$(var3)))
> 
> was erroneous, but
>   $(var1$(var2))
> 
> was not.  Also, with a one-character variable X
>   $(var$X)
> 
> was erroneous with at least one legacy make implementation (but I think
> it was more than one); but
>   $(var$(X))
> 
> worked.
> 
> If you like, I can go back and verify the details.

Yes please, and I will feed that information back to the Austin Group.
It may result in a wording modification and a restart of the 30-day
review window (changing the wording proposal to explicitly leave the
problematic corner cases unspecified) so that the goal of including the
change as part of the technical corrigendum 1 of POSIX 2008 (probably
coming by late 2011) will not invalidate existing implementations; or it
may result in the Austin Group deferring the change to the next full
revision of the standard (several years out) to give those
implementations time to comply with a tighter standard.

-- 
Eric Blake   address@hidden    +1-801-349-2682
Libvirt virtualization library http://libvirt.org

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