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Re: [Bug-gnulib] Patch proposal: 1-gary-safe-xfree.patch

From: Gary V . Vaughan
Subject: Re: [Bug-gnulib] Patch proposal: 1-gary-safe-xfree.patch
Date: Tue, 16 Sep 2003 09:17:21 +0100

On Monday, September 15, 2003, at 09:21  pm, Paul Eggert wrote:

they are none-the-less genuinely useful shorthand that can't be done
without macros. Do you have a similar replacement functionality in
mind?  Or do you find macros like these to be worse than the extra
typing that would be required in their absence?

Yes, because code is clearer when function-like macros act like functions.

Also, less typing is often required if you avoid the macros.  For
example, compare this code (taken from GNU m4):

  new = XMALLOC (macro_definition, 1);

to this proposed replacement:

  new = xmalloc (sizeof *new);

The latter style is shorter in this case.  (In other cases it's
longer, of course.)  Another advantage of the latter style is that
it's immune to changes in the type of the variable.

Okay, sold!  Thanks for the explanation :-)

Here's a proposed patch to GNU m4 to let it survive the loss of the
macros in question, so that you can see how much the code is actually

It is surprising to see how little effect it has in practice, I have to say. Once the free module is in gnulib, I'll resynch m4 and apply your patch. Thanks again!

Aside: I notice that m4, after the proposed patch, uses calloc (1, S)
a lot.  Perhaps we should define a new zalloc (S) that is equivalent
to calloc (1, S), for convenience?  I've used zalloc in other

If zalloc (S) === xcalloc (1, S), that would be cool. Failing that we could always add an XZALLOC macro... :-b

  ())_. Gary V. Vaughan     gary@(oranda.demon.co.uk|gnu.org)
( '/ Research Scientist http://www.oranda.demon.co.uk ,_())____ / )= GNU Hacker http://www.gnu.org/software/libtool \' `& `(_~)_ Tech' Author http://sources.redhat.com/autobook =`---d__/

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