On Tue, Feb 7, 2012 at 12:18, Stefan Hajnoczi <stefa...@gmail.com> wrote: > On Sat, Jan 28, 2012 at 9:31 AM, Alex Barcelo <abarc...@ac.upc.edu> wrote: >> On Fri, Jan 27, 2012 at 15:39, Paolo Bonzini wrote: >>>> I have a patch that uses sigsetjmp and siglongjmp instead of >>>> makecontext and getcontext (and all the ucontext stuff), and it >>>> *seems* to work... but I'm not sure if it works "by accident" (not >>>> sure what I'm doing to the stack, not sure what I should be doing to >>>> the stack). >>> >>> You can post it, don't worry. I'm curious how you are switching stacks when >>> creating the coroutine. >>> >> >> I think that I'm not switching, so at first I didn't understand why >> could it run at all. Now I think that qemu-img is too simple and a new >> stack is not really needed (probably only one coroutine and >> straightforward, I'll check it). So it doesn't crash. >> >> Thank you very much for the advice and comments. I'll do some more >> tests, I expect to achieve something useful ^^ > > The way that you can use the setjmp/longjmp family of functions for > creating stacks is by manipulating the fields inside jmpbuf. However, > it seemed slightly more portable and less hacky to use ucontext > functions instead of doing that. > > Stefan
Yes, I agree. But makecontext and swapcontext are not OK for my project (mainly because makecontext and swapcontext are not supported by qemu under PPC) so I was looking for alternatives. My best shot at the moment is using sigaltstack, if it works I will post a patch for coroutines using sigaltstack, which is also quite portable (GNU Portable Thread can use both, so I was trying to copy its functionality). Alex
