[vox-tech] location of DBL_EPSILON definition

Peter Jay Salzman p at dirac.org
Fri Jan 26 11:35:26 PST 2007


On Fri 26 Jan 07,  9:04 AM, Boris Jeremic <jeremic at ucdavis.edu> said:
> on my machine (fedora core 5) there are definitions in
> 
> ./usr/lib/gcc-lib/i386-redhat-linux/3.2.3/include/float.h
> 
>    /* Difference between 1.0 and the minimum double greater than 1.0 */
> #undef DBL_EPSILON
> #define DBL_EPSILON 2.2204460492503131e-16
> 
> 
> 
> but not in
> 
> ./usr/lib/gcc/i386-redhat-linux/4.1.0/include/float.h
> 
> where it appears as:
> 
> /* The difference between 1 and the least value greater than 1 that is
>    representable in the given floating point type, b**1-p.  */
> #undef FLT_EPSILON
> #undef DBL_EPSILON
> #undef LDBL_EPSILON
> #define FLT_EPSILON	__FLT_EPSILON__
> #define DBL_EPSILON	__DBL_EPSILON__
> #define LDBL_EPSILON	__LDBL_EPSILON__
 

It's in neither place for me.
 
> You can also calculate them yourself:

Yeah, I'm aware of that, but this is not what I wanted.

It's not DBL_EPSILON that I care about (I simplified my question).  I wanted
a file that I could look at and know any of the constants that are of
interest to me.  It's not one constant I wanted to know, but all of them, in
one place.


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