digitalmars.D.bugs - [Issue 308] New: Documentation of float.max_exp, min_exp is misleading
- d-bugmail puremagic.com (30/30) Aug 24 2006 http://d.puremagic.com/issues/show_bug.cgi?id=308
- d-bugmail puremagic.com (9/9) Sep 09 2006 http://d.puremagic.com/issues/show_bug.cgi?id=308
- Don Clugston (5/20) Sep 12 2006 Because they are the same values that C compilers return. Eg Visual C++
- d-bugmail puremagic.com (4/4) Sep 13 2006 http://d.puremagic.com/issues/show_bug.cgi?id=308
-
Don Clugston
(9/17)
Sep 13 2006
They're in
. They don't have the same syntactic sugar as D, of - d-bugmail puremagic.com (5/5) Sep 14 2006 http://d.puremagic.com/issues/show_bug.cgi?id=308
- d-bugmail puremagic.com (9/9) Sep 19 2006 http://d.puremagic.com/issues/show_bug.cgi?id=308
http://d.puremagic.com/issues/show_bug.cgi?id=308
Summary: Documentation of float.max_exp, min_exp is misleading
Product: D
Version: 0.165
Platform: PC
OS/Version: Windows
Status: NEW
Severity: trivial
Priority: P2
Component: DMD
AssignedTo: bugzilla digitalmars.com
ReportedBy: clugdbug yahoo.com.au
The documentation describes min_exp as the "minimum exponent as power of 2",
but this is not correct, and it implies that real.min == pow(2, min_exp), but
actually real.min == pow(2, min_exp-1).
Likewise,
pow(2, max_exp-1) < real.max < pow(2, max_exp)
Perhaps change the definitions to be:
"minimum exponent as a power of 2, plus 1".
"maximum exponent as a power of 2, plus 1".
since they are really non-intuitive (see listing below).
Any idea why they've always been defined in C in such a bizarre way?
---
writefln(real.min_exp, " %a", real.min, " ", real.max_exp, " %a", real.max, "
");
writefln(double.min_exp, " %a", double.min, " ", double.max_exp, " %a",
double.max);
writefln(float.min_exp, " %a", float.min, " ", float.max_exp, " %a",
float.max);
--
Aug 24 2006
http://d.puremagic.com/issues/show_bug.cgi?id=308
smjg iname.com changed:
What |Removed |Added
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CC| |smjg iname.com
How do you know it's the spec that's wrong and not the complier? Moreover, why
are they min_exp and max_exp, not minExp and maxExp as per naming conventions?
--
Sep 09 2006
Don Clugston <dac nospam.com.au>
d-bugmail puremagic.com wrote:
http://d.puremagic.com/issues/show_bug.cgi?id=308
smjg iname.com changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |smjg iname.com
How do you know it's the spec that's wrong and not the complier? Moreover, why
are they min_exp and max_exp, not minExp and maxExp as per naming conventions?
Because they are the same values that C compilers return. Eg Visual C++
returns the same values. I don't know why C ended up with such a
ridiculous definition, but those are the values used on all C/C++
compilers that I know of.
Sep 12 2006
http://d.puremagic.com/issues/show_bug.cgi?id=308 I could've sworn C didn't have any kind of properties on built-in types. --
Sep 13 2006
d-bugmail puremagic.com wrote:http://d.puremagic.com/issues/show_bug.cgi?id=308 I could've sworn C didn't have any kind of properties on built-in types.They're in <float.h>. They don't have the same syntactic sugar as D, of course. #define FLT_MAX_EXP 128 #define FLT_MIN_10_EXP -37 #define FLT_MIN_EXP -125 #define DBL_MAX_EXP 1024 #define DBL_MIN_EXP -1021 etc.
Sep 13 2006
http://d.puremagic.com/issues/show_bug.cgi?id=308 They have different notations, so AFAIC there's no reason to assume that they're supposed to be the same. --
Sep 14 2006
http://d.puremagic.com/issues/show_bug.cgi?id=308
bugzilla digitalmars.com changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |FIXED
Fixed in DMC 0.167.
--
Sep 19 2006