• Zhenya (2/2) Dec 28 2012 Hi!
• bearophile (4/5) Dec 28 2012 http://dlang.org/phobos/std_math.html#isNaN
• Zhenya (2/8) Dec 28 2012 Thank you!
• Red (5/8) Dec 28 2012 pure nothrow @trusted bool isNaN(real x);
• Simen Kjaeraas (14/16) Dec 28 2012 us std.math.isNaN. But if you really don't want to:
• Zhenya (3/20) Dec 28 2012 Thank you,understood)

"Zhenya" <zheny list.ru> writes:

Hi!
Tell me please,are there any way to check whether number is NaN?

"bearophile" <bearophileHUGS lycos.com> writes:

Zhenya:

 Tell me please,are there any way to check whether number is NaN?

http://dlang.org/phobos/std_math.html#isNaN

Bye,
bearophile

"Zhenya" <zheny list.ru> writes:

On Friday, 28 December 2012 at 15:59:35 UTC, bearophile wrote:
 Zhenya:

 Tell me please,are there any way to check whether number is 
 NaN?

 http://dlang.org/phobos/std_math.html#isNaN

 Bye,
 bearophile

Thank you!

"Red" <resmith lavabit.com> writes:

 Tell me please,are there any way to check whether number is 
 NaN?

 http://dlang.org/phobos/std_math.html#isNaN


pure nothrow  trusted bool isNaN(real x);

Returns !=0 if e is a NaN.

-------------------
Seems like a slight documentation disagreement. Shows bool 
prototype but description says returns !=0

"Simen Kjaeraas" <simen.kjaras gmail.com> writes:

On 2012-42-28 16:12, Zhenya <zheny list.ru> wrote:

 Hi!
 Tell me please,are there any way to check whether number is NaN?

us std.math.isNaN. But if you really don't want to:

float x = ...;

if (x != x) {
     writeln( "x is NaN" );
}

I'm unsure how aggressive the optimizer is allowed to be in cases
like this. Theoretically it could assume x is always equal to x,
but I'd think it's not allowed to for floats.

If you're wondering how a float value could compare different to
the exact same value, consider that this would otherwise be true:

sqrt(-1) == 0/0

-- 
Simen

"Zhenya" <zheny list.ru> writes:

On Friday, 28 December 2012 at 20:19:49 UTC, Simen Kjaeraas wrote:
 On 2012-42-28 16:12, Zhenya <zheny list.ru> wrote:

 Hi!
 Tell me please,are there any way to check whether number is 
 NaN?

 us std.math.isNaN. But if you really don't want to:

 float x = ...;

 if (x != x) {
     writeln( "x is NaN" );
 }

 I'm unsure how aggressive the optimizer is allowed to be in 
 cases
 like this. Theoretically it could assume x is always equal to x,
 but I'd think it's not allowed to for floats.

 If you're wondering how a float value could compare different to
 the exact same value, consider that this would otherwise be 
 true:

 sqrt(-1) == 0/0

Thank you,understood)
It's a nice way.