Casting double to ulong weirdness

[Justin Whear via Digitalmars-d]

On Mon, 24 Aug 2015 18:06:07 +0000, rumbu wrote:

> BTW, 1.2 and 12.0 are directly representable as double
> 
> In C++:
> 
> printf("%.20f\r\n", 1.2);
> printf("%.20f\r\n", 12.0);
> 
> will output:
> 
> 1.20000000000000000000 12.00000000000000000000
> 
> Either upcasting to real is the wrong decision here, either the writeln
> string conversion is wrong.

No it's not, this must be some sort of constant-folding or precision 
increase.

$ cat test.c
#include "stdio.h"

int main(int nargs, char** args)
{
		double x = 1.2;
			printf("%.20f\n", x);
}

$ clang test.c && ./a.out
1.19999999999999995559