Strange Thread Causing Duplicating `writeln`

[Steven Schveighoffer]

On 4/9/18 6:56 PM, Jonathan wrote:
> On Monday, 9 April 2018 at 22:53:31 UTC, Jonathan wrote:
>> On Monday, 9 April 2018 at 22:49:07 UTC, Cym13 wrote:
>>> I don't know, but I can't reproduce either with dmd or ldc. What was 
>>> your compilation line?
>>
>> dmd -run file.d
> 
> I am on Window 10 btw.

It's a windows 32-bit issue (specifically, DMC's FILE *, upon which 
std.stdio.File is based, is thread unsafe).

Try -m64.

https://issues.dlang.org/show_bug.cgi?id=18483
http://bugzilla.digitalmars.com/issues/show_bug.cgi?id=327

-Steve