Concurrency Confusion

[Chris via Digitalmars-d-learn]

On Saturday, 8 August 2015 at 00:39:57 UTC, 岩倉 澪 wrote:
> On Friday, 7 August 2015 at 22:13:35 UTC, 岩倉 澪 wrote:
>> "message" is local to the delegate that receiveTimeout takes.
>> I want to use "message" outside of the delegate in the 
>> receiving thread. However, if you send an immutable value from 
>> the worker thread, afaict there would be no way to assign it 
>> to a global/outer variable without making a mutable copy 
>> (expensive!)
>> I haven't really spent much time trying to pass my "message" 
>> as mutable via shared yet, but hopefully that could work...
>
> Found the answer to this :) 
> http://forum.dlang.org/post/mailman.1706.1340318206.24740.digitalmars-d-learn@puremagic.com
>
> I send the results from my worker thread with assumeUnique, and 
> then simply cast away immutable in the receiving thread like so:
>
> (in module scope)
>     Bar[] baz;
>
> (in application loop)
>     import std.array
>     if(baz.empty)
>     {
>         import std.concurrency, std.datetime;
>         receiveTimeout(0.msecs,
>                 (immutable Bar[] bar){ baz = cast(Bar[])bar; });
>     }

Note aside: if you only import what you need (say `import 
std.concurrency : receiveTimeout; std.datetime : msecs`), you can 
reduce the size of the executable considerably as your program 
grows.