context

It is an OS component, it's provided in kernel32.dll and accesses internal OS data structures that are not publicly defined or stable between versions. You cannot safely implement fibers in Windows without the fibers API, period. Boost.Context's direct Windows context switching code hacks undocumented fields in the TIB: https://github.com/boostorg/context/blob/6fa6d5c50d120e69b2d... ...and this causes problems, because it can't guarantee that all fields are initialized or switched successfully: https://lists.boost.org/boost-bugs/2014/10/38476.php Microsoft continually adds and changes fields in the TIB with each new release of Windows. Attempting to implement fibers manually is a ticking time bomb that should never be used in production.

Would be nice to compare performance with others libraries! For example Stacklet [0] and Boost Context [1]. - [0] https://github.com/mozillazg/pypy/tree/master/rpython/transl... - [1] https://github.com/boostorg/context/tree/develop/src/asm