Hello. I found unexpected (for me) behavior of rounding double
values at casting to ulong:
$ cat roundtest.d
import std.stdio;
void main()
{
double a = 10, b = 0.01;
writeln( "int: ", cast(int)(a/b) );
writeln( "uint: ", cast(uint)(a/b) );
writeln( "long: ", cast(long)(a/b) );
writeln( "ulong: ", cast(ulong)(a/b) );
}
$ rdmd roundtest.d
int: 1000
uint: 1000
long: 1000
ulong: 999 <----- WTF?? -------
$ dmd --version
DMD64 D Compiler v2.067.1
Copyright (c) 1999-2014 by Digital Mars written by Walter Bright
$ ldc2 roundtest.d && ./roundtest
int: 1000
uint: 1000
long: 1000
ulong: 1000 <------- Ok --------
$ ldc2 --version
LDC - the LLVM D compiler (0.15.2-beta1):
based on DMD v2.066.1 and LLVM 3.6.0
Default target: x86_64-unknown-linux-gnu
Host CPU: core-avx-i
http://dlang.org - http://wiki.dlang.org/LDC
Registered Targets:
x86 - 32-bit X86: Pentium-Pro and above
x86-64 - 64-bit X86: EM64T and AMD64
$ uname -a
Linux lenovo 4.0.4-201.fc21.x86_64 #1 SMP Thu May 21 15:58:47 UTC
2015 x86_64 x86_64 x86_64 GNU/Linux
have it behavior explain? can I use casting in dmd for rounding
values or it not safe?
