[libdispatch-dev] autoconf HAVE macro conventions

Kevin Van Vechten kvv at apple.com
Fri Oct 30 12:44:15 PDT 2009

On Oct 30, 2009, at 12:26 PM, Paolo Bonzini wrote:

> On 10/30/2009 08:24 PM, Kevin Van Vechten wrote:
>> I'm not very familiar with autoconf conventions and was wondering why
>> some config.h values are merely defined and some are explicitly
>> defined to 1.
> That's a bad decision in configure.ac usually.  Just look for occurrences of AC_DEFINE([FOO],,[Comment]) and add a 1 between the two commas.


>> Is there a strong convention to do #ifdef HAVE_FOO instead of #if
>> HAVE_FOO when testing for configure features?  For various reasons,
>> the ability to define a macro to 0 or 1 would be useful for the Mac
>> OS X version of config.h — it would let us define certain features in
>> terms of other features without as much conditional logic.
> ... that said, why can't config.h be generated for Mac OS X by running configure every time a change to the autoconf source is checked in? There should be no need for conditional logic.

Although autoconf doesn't suit our needs when building libdispatch as a part of Mac OS X for a variety of reasons, we're happy to have autoconf in our source tree to due to its importance on other platforms.


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