Re: How to get AC_DEFINE to generate a macro, e.g., #define incr(x) ((x)+1) ?

[Steven G. Johnson]

Thien-Thi Nguyen wrote:
> Fred Proctor <address@hidden> writes:
>
> > How can one get AC_DEFINE to define a variable with an argument
> > list?  I want to do something like this:
> >
> > AC_DEFINE(incr(x),((x)+1),"increment")
>
> i think either you misunderstand AC_DEFINE or i misunderstand you.
> where in the documentation is the possibility of such a construct
> suggested?

Actually, it *is* possible to define macros+arguments with autoconf 
(version 2.50 or later); in fact, that's how autoconf itself defines 
F77_FUNC etcetera for AC_F77_WRAPPERS.  However, you are correct in that 
(I think) it's not adequately documented.

As for the original poster's code, there are three problems that are 
preventing it from working.  (1) It's underquoted.  (2) "incr" is an m4 
built-in, so that causes extra breakage unless you rename your macro. 
(3) When using AC_DEFINE for a macro, you need to use AH_TEMPLATE to 
give its config.h.in template separately.  The following works for me:

        AH_TEMPLATE([INCR], [increment])
        AC_DEFINE([INCR(x)], [((x)+1)])

Cordially,
Steven G. Johnson