Re: autoconf 2.61: AC_DEFINE variable with parenthesis

[Steven G. Johnson]

Paul Eggert wrote:
> But there are at least two regressions here.  First, the one reported
> by Andrey Simonenko in
> <http://lists.gnu.org/archive/html/bug-autoconf/2006-12/msg00026.html>,
> where AC_DEFINE([DEF(x)], [somevalue]) does not work in Autoconf 2.61
> as it did in Autoconf 2.59.  Second, the one I introduced in
> <http://lists.gnu.org/archive/html/bug-autoconf/2006-12/msg00031.html>,
> which explicitly generates a warning when you invoke
> AC_DEFINE([DEF(x)], [somevalue]).

Ah, I didn't notice that you had added this warning.

Regarding Andrey Simonenko's complaint, it has to do with old-style 
#define templates in the config.h.in file, which are now deprecated 
according to the manual.  In particular, he was relying on the old (no 
longer documented?) behavior that if you #define VAR VALUE in the .h.in 
file then it gets replaced, but it doesn't get replaced if you do just 
#define VAR [no value].  He wanted to do the same thing for a macro with 
arguments, i.e. #define VAR(args) [no value] and have it not be 
replaced.  I'm not sure what is the rationale to support this 
deprecated, no-longer-documented behavior in the context of a "new" 
feature (macros with arguments).  (It's not a regression since it was 
never documented.)

However, the source of this "regression" (if you want to call it that) 
seems to be revision 1.83 of status.m4 (see your 2006-01-06 entry in the 
ChangeLog).  In particular, prior to that change, the conftest.defines 
sed pattern skipped to the close-parenthesis (if there was an 
open-parenthesis after the macro name) before checking to see whether 
the #define had a value.  It would be fairly easy to go back to this 
behavior if we wanted to, I guess, but I don't really see the point.

Regarding the second problem, I have fixed it in the attached patch.  In 
particular, it now always traces just the name of the macro, not 
including the argument list, matching the behavior of AH_TEMPLATE.

Attached is a patch, with ChangeLog entry below.

Steven

2006-12-28  Steven G. Johnson  <address@hidden>

        * lib/autoconf/general.m4 (AC_DEFINE_TRACE): Don't include
        preprocessor macro arguments in traced name.
        * doc/autoconf.texi (Defining symbols): Document longstanding
        support for AC_DEFINE-ing macros with arguments, and document
        behavior when the same variable has multiple AC_DEFINEs.
        * lib/autoconf/fortran.m4 (_AC_FC_WRAPPERS): Revert to the
        old implementation which AC_DEFINEs the FC_FUNC and FC_FUNC_
        macros directly, giving much shorter and simpler code.

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