On Friday, 20 April 2012 at 17:49:52 UTC, Sean Kelly wrote:
There wouldn't me much of a performance hit, mostly an
additional allocation and a bitcopy when creating a Fiber.
It's more that making this work on platforms with built-in TLS
could be quite tricky.
Note that this would somewhat sabotage their usefulness as
coroutines, depending on how it was implemented. That's not to
say the idea isn't good (but I'd frame it more like "tasks"; see
Thread Building Blocks or similar), but fibers/coroutines as they
stand now are useful so I'd hate to see that capability lost.