Hello, A while ago, I implemented the Boost.Thread API in terms of Windows Fibers and <uncontext.h> functionality. The result is the ability to run code written with boost threads in a single OS thread. I find it useful for writing tests where determinism is important i.e. to test algorithmic correctness in isolation from synchronization- related concerns. I haven't updated it to mirror the new 1.35 API yet, but I was wondering if any other boost users would be interested in this or if it might be thought suitable for inclusion in the boost library collection. More information is available here: http://www.mr-edd.co.uk/?page_id=91 Direct link to source code: http://www.mr-edd.co.uk/files/coco/coco-0.2.0.zip Kind regards, Edd