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Re: [vox-tech] location of DBL_EPSILON definition
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Re: [vox-tech] location of DBL_EPSILON definition



I already know the names of all my constants and what they mean.  I wanted a
file that I could open and peek at numerical values.  No gcc, no web
browser.  Just some float.h that I can open with vim, less, or grep to
quickly get a value in 2 seconds.

Such a float.h used to exist on my hard drive.  I guess that changed with
some gcc update.

Telling me to read the IEEE 754 standard is like telling me that I need to
know the DNA sequence for a Fuji apple when all I really want is to eat one.

Peter



On Mon 29 Jan 07,  8:58 AM, Boris Jeremic <jeremic@ucdavis.edu> said:
> Then you need to read IEEE 754 (and accompanying documents...):
> 
> 
> http://grouper.ieee.org/groups/754/
> 
> 
> Boris
> 
> 
> Peter Jay Salzman wrote:
> >On Fri 26 Jan 07,  9:04 AM, Boris Jeremic <jeremic@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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