MS C ++编译器出现错误的FP错误 [英] Bad FP error with MS C++ compiler

问题描述

// MS-Bug＃999,995（剩下5个错误： - ）：


const double d = DBL_MIN;


double v00 = 0.0;

bool f00 = v00 d;


double v01 = 0.1;

bool f01 = v01 d ;


为f00错误地给出''false'':-)

解决方案

" Adem24" < ad **** @ adem24.org.invalidwrote：

// MS-Bug＃999,995（剩下5个错误:-)：


const double d = DBL_MIN;


double v00 = 0.0;

bool f00 = v00 d;


double v01 = 0.1;

bool f01 = v01 d;


为f00错误地''false''。 .. :-)

错误在您的代码中。 DBL_MIN是一个最小的正值。


Alex

" Adem24"写道：

>

// MS-Bug＃999,995（剩下5个错误:-)：


const double d = DBL_MIN;


double v00 = 0.0;

bool f00 = v00 d;


double v01 = 0.1;

bool f01 = v01 d;


为f00错误地''false''... :-)

进一步的分析显示它与DBL_MIN没什么关系

但是值为ZERO！

即。 MS编译器在FP操作中不正确地处理值0.

在7月20日16:10，Adem24 < ade ... @ adem24.org.invalidwrote：

// MS-Bug *＃999,995（剩下5个错误:-)：

或Adem24 bug＃3562？

>

* * * * const double d = DBL_MIN;

d大于0：或许它有助于阅读文档？

>

* * * * double v00 = 0.0;

* * * * bool * f00 = v00 d;


* * * * double v01 = 0.1;

* * * * bool * f01 = v01 d;


为f00错误地''false''... :-)

f00应该是真的。


/ Peter

// MS-Bug # 999,995 (5 left for 1 million bugs :-) :

const double d = DBL_MIN;

double v00 = 0.0;
bool f00 = v00 d;

double v01 = 0.1;
bool f01 = v01 d;

gives wrongly ''false'' for f00... :-)

解决方案

"Adem24" <ad****@adem24.org.invalidwrote:

// MS-Bug # 999,995 (5 left for 1 million bugs :-) :

const double d = DBL_MIN;

double v00 = 0.0;
bool f00 = v00 d;

double v01 = 0.1;
bool f01 = v01 d;

gives wrongly ''false'' for f00... :-)

The bug is in your code. DBL_MIN is a minimal positive value.

Alex

"Adem24" wrote:

>
// MS-Bug # 999,995 (5 left for 1 million bugs :-) :

const double d = DBL_MIN;

double v00 = 0.0;
bool f00 = v00 d;

double v01 = 0.1;
bool f01 = v01 d;

gives wrongly ''false'' for f00... :-)

Further analysis shows that it has nothing todo with the DBL_MIN
but the value ZERO !
Ie. the MS compiler treats the value 0 not correctly in FP ops.

On 20 Jul., 16:10, "Adem24" <[e-mail]:

// MS-Bug *# 999,995 (5 left for 1 million bugs :-) :

Or Adem24 bug# 3562?

>
* * * *const double d = DBL_MIN;

d is bigger than 0: perhaps it would help to read the documentation?

>
* * * *double v00 = 0.0;
* * * *bool * f00 = v00 d;

* * * *double v01 = 0.1;
* * * *bool * f01 = v01 d;

gives wrongly ''false'' for f00... :-)

f00 should be true.

/Peter

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