Casting double to ulong weirdness

[rumbu via Digitalmars-d]

On Monday, 24 August 2015 at 17:26:12 UTC, Steven Schveighoffer 
wrote:
>
> Note, this is NOT a D problem, this is a problem with floating 
> ponit. And by problem, I mean feature-that-you-should-avoid :)
>
> -Steve

Visual C++ 19.00.23026, x86, x64:

int _tmain(int argc, _TCHAR* argv[])
{
	double x = 1.2;
	printf("%d\r\n", (unsigned long long)(x * 10.0));
         double y = 1.2 * 10.0;
         printf("%d\r\n", ((unsigned long long)y));
	return 0;
}

Output:
12
12

Same output in debugger for an ARM Windows App.

C# 6.0:

static void Main(string[] args)
{
         double x = 1.2;
         WriteLine((ulong)(x * 10.0));
         double y = 1.2 * 10.0;
         WriteLine((ulong)y);
}

Output:
12
12

Same output in debugger for ARM in all flavours (Android, iOS, 
Windows)

It seems like a D problem.