Mike Elkins Mike Elkins - 24 days ago 6
C++ Question

How do you implement Coroutines in C++

I doubt it can be done portably, but are there any solutions out there? I think it could be done by creating an alternate stack and reseting SP,BP, and IP on function entry, and having yield save IP and restore SP+BP. Destructors and exception safety seem tricky but solvable.

Has it been done? Is it impossible?

Answer

Yes it can be done without a problem. All you need is a little assembly code to move the call stack to a newly allocated stack on the heap.

I would look at the boost::coroutine library.

The one thing that you should watch out for is a stack overflow. On most operating systems overflowing the stack will cause a segfault because virtual memory page is not mapped. However if you allocate the stack on the heap you don't get any guarantee. Just keep that in mind.

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