On 08/26/2010 09:43 AM, Gary V. Vaughan wrote:
Hi Eric,
On 26 Aug 2010, at 20:45, Eric Blake wrote:
Not true, if $TMPDIR already has a value that contains globbing characters (of
course, the likelihood of this is slim, but the whole point of ${a=b} is that
you are assigning a value to $a _if_ it doesn't already have one, which implies
that you are also admitting that $a may already have an unspecified value
inherited from the user - and we know that it is never a good idea to blindly
trust user input to be sane.
Ah-hah! The penny has dropped... now I see why the outer quotes are worthwhile.
Thanks for the explanation.
If you didn't do it already (I didn't go over the follow-up patches as
carefully, so I might have missed it), I think some version of the above added
to the Autoconf manual would make it easier for others to understand what the
difference is, and internalise the advantages of using outer quotes when
possible.
Yes, adding that extra timing example (for when a variable is inherited
rather than defaulted) does make sense. I'll fold that in.
--
Eric Blake ebl...@redhat.com +1-801-349-2682
Libvirt virtualization library http://libvirt.org
