Re: [OpenBabel-Devel] C99 (was forcefield classes)

[Geoffrey H. <ge...@ge...>]

On Feb 20, 2007, at 4:01 PM, Carsten Niehaus wrote:

>> isnan() is included in the C99 standard as far I know. If this is
>> unavailable
>>
>> #define *isnan*(x) ((x) != (x))

> What is the policy about OpenBabel and C99? For KDE4, C99 is still  
> not allowed
> because the compiler/libs we use on all the differnt platforms  
> (linux, *bsd,
> AIX, IRIX, windows, MacOS...) do in parts not support it... As OB  
> has the

No, this is a good point. Not all compilers support C99 syntax, so we  
should attempt to not use it, or provide workarounds.

For example, autoconf suggests a slightly different approach:
http://www.gnu.org/software/autoconf/manual/html_node/Function- 
Portability.html

> #include <math.h>
>
>           #ifndef isnan
>           # define isnan(x) \
>               (sizeof (x) == sizeof (long double) ? isnan_ld (x) \
>                : sizeof (x) == sizeof (double) ? isnan_d (x) \
>                : isnan_f (x))
>           static inline int isnan_f  (float       x) { return x !=  
> x; }
>           static inline int isnan_d  (double      x) { return x !=  
> x; }
>           static inline int isnan_ld (long double x) { return x !=  
> x; }
>           #endif

-Geoff