Re: isnan in fortran

[Jordi Gutiérrez Hermoso]

On 10 April 2012 08:28, Mike Miller <address@hidden> wrote:
> On Tue, Apr 10, 2012 at 12:44:07PM +0200, c. wrote:
>> I am regularly building Octave on OSX withg gcc/gfortran 4.2.1
>> [...]
>> I need to locally apply the following patch (which I keep in my hq
>> patch queue), as gfortran 4.2 does not have isnan:
>> [...]
>> Does anyone know a cleaner and portable way how these functions
>> could be made to work with fortran compilers that do not have
>> ISNAN?
>
> I run into the same problem, RHEL 5.x with gcc 4.1.2.
[snip]
> A quick search suggests (X.NE.X) may be the best alternative, at
> least for IEEE 754 systems.

Can Fortran be preprocessed? If so, can we write an autoconf macro to
check for isnan and use X.NE.X if not?

- Jordi G. H.