Re: HAVE_FFTW macro

[Daniel J Sebald]

On 03/17/2013 03:47 AM, John W. Eaton wrote:
> On 03/17/2013 04:33 AM, Daniel J Sebald wrote:
> > On 03/16/2013 11:20 PM, Rik wrote:
> > > On 03/16/2013 12:52 AM, address@hidden wrote:
> > > > > Is something being overlooked there?
> > > > What does
> > > >
> > > > octave_config_info ("features")
> > > >
> > > > show? This is a list of all the HAVE_X macros, with the common "HAVE_"
> > > > part omitted. On my system, it has FFTW3, but not FFTW, so it looks
> > > > like the testif check is wrong.
> > > Dan,
> > >
> > > The problem seems to be that not all #defines are captured in the new
> > > "features" keyword. The definition for HAVE_FFTW is in configure.ac in
> > > the
> > > AH_BOTTOM macro which means it is copied to the bottom of config.h.
> > >
> > > /* Octave is currently unable to use FFTW unless both float
> > > and double versions are available. */
> > > #if defined (HAVE_FFTW3)&& defined (HAVE_FFTW3F)
> > > #define HAVE_FFTW
> > > #endif
> > >
> > > I wasn't following closely what jwe did when he added the "features"
> > > keyword, but hopefully it is simple to fix.
> >
> > OK, thanks. Probably in over my head had I looked for that. But now that
> > you point out the test above I think I see what the problem is. The test
> > is "defined". Both of those variables appear to be defined, if I'm
> > following correctly, but they are given the value 0, i.e.,
> >
> > FFTW3 = 0
> > FFTW3F = 0
> >
> > So maybe either the test should be something other than defined() and
> > instead check the value of the FFTW3, FFTW3F, or FFTW3 and FFTW3F should
> > be left undefined rather than setting them to 0.
> >
> > Dan
>
> Does your generated config.h file really have
>
> #define HAVE_FFTW3 0
>
> ? Or is it
>
> /* #undef HAVE_FFTW3 */
>
> The latter is what I have.

OK, you're right:

/* Define to 1 if FFTW3 is available. */
/* #undef HAVE_FFTW3 */

So a 0 in the "features" config info means not defined but it is a 
possible feature?

Is the "undef" important.  The commented-out undef sort of suggests the 
norm is to have HAVE_X defined whereby uncommenting will cause HAVE_X to 
be undefined.  That is, instead of uncommenting the line, the action is 
to change the line to

#define HAVE_FFTW3 1

Why not have:

/* Define to 1 if FFTW3 is available. */
/* #define HAVE_FFTW3 1 */


Not super important.


> Anyway, I think I have a fix for the original problem. Once I'm doing
> testing, I'll push it.

OK, I'll try it out in the morning.

Dan