libCoroutine is a C library that implements support for CoRoutine**’s. It is part of the IoLanguage. It partially supports OS X (it does not correctly handle floating-point and vector registers).

Homepage: http://www.dekorte.com/projects/opensource/libCoroutine/

Download: http://www.dekorte.com/projects/opensource/libCoroutine/libcoroutine.tgz