Proposal: Exceptions and @nogc

[Walter Bright via Digitalmars-d]

On 4/3/2017 2:38 PM, David Nadlinger wrote:
> On Monday, 3 April 2017 at 21:00:53 UTC, Walter Bright wrote:
>> The idea of this proposal is to make a nogc program much more achievable.
>> Currently, in order to not link with the GC, you can't use exceptions (or at
>> least not in a memory safe manner). A solution without memory safety is not
>> acceptable.
>
> You could use an exception instance allocated in TLS (which is, in fact, what
> Weka does in large parts of the code). This should be perfectly memory safe,
> although there are of course implications for exception chaining. (By default,
> you'll still get an allocation for the associated TraceInfo, but you can disable
> that.)
>
> Of course, this is not to say that a nicer/more general solution wouldn't be
> appreciated.
>
>  — David

Using a singleton in TLS is indeed memory safe, as long as you don't do things 
like keep a reference to it around and expect it not to change.