Home » forums » LtU Forum

Delimited continuations for C/C++

Hello LtU,

I have created a monster. I have implemented a variant of shift/reset control operators, shift0/reset0, for C/C++. The core of the implementation is written in x86 assembly and works by heap-allocating new stacks and switching between them. There are some caveats, but otherwise everything seems to be working nice.

I've shared the implementation on github. Could you take a look at it and share some comments?

(And yes, I know this is crazy.)

By tilk at 2011-11-28 14:38 | LtU Forum | previous forum topic | next forum topic | other blogs | 8911 reads

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

I am very interested.

Thanks for posting this! Sounds like exactly what I want. I will have a look and tell you what I think.

Are the thunks garbage-collected?

By Denis Bredelet -jido at Tue, 2011-11-29 19:47 | login or register to post comments

No garbage collection

The user is responsible for freeing the captured continuations. You could probably use some external garbage collector, if you need it.

By tilk at Wed, 2011-11-30 10:28 | login or register to post comments

Stack manipulation in semi-portable C

You can allocate stacks and switch between them using setjmp, longjmp, and either alloca() or variable-size local arrays to adjust the stack pointer into a new section of memory. See some example code i posted to my blog a while back. To allocate the stack on the heap, calculate a new top-of-stack using malloc() instead of arithmetic on a stack location.

By Tony Finch at Tue, 2011-11-29 22:36 | login or register to post comments

libconcurrency is along the

libconcurrency is along the same lines. You can find fibers (for Windows), stack-copying (which is the most portable), and stack-switching backends in 100% C. Your approach looks like an interesting variant though, so I'll have to digest it further.

By naasking at Wed, 2011-11-30 01:09 | login or register to post comments