Re: [HACKERS] snapshot and FreeBSD-2.2.7 not building - Mailing list pgsql-hackers

Bruce Momjian <maillist@candle.pha.pa.us> writes:

> I am now generating NAN by:
> 
>     double x;
> 
>     return (x-x)/(x-x);
> 
> This seems to be the way my libm math library does it.  The gcc2 -O4
> compile does not seem to optimize it away, so looks like it will work. 
> My guess is that the compiler can not optimize floating-point
> computations.

Thanks for the follow-up. Suggestion:

At the top of numeric.c or in include/utils/numeric.h, put

#ifndef NAN
#define pgNAN (0.0/0.0)
#endif

Then in numeric.c, if NAN isn't defined,
return pgNAN;

--
Hal