libdispatch is Open Source for a long time now: <a href="http:&#x2F;&#x2F;www.osnews.com&#x2F;story&#x2F;22152&#x2F;Apple_Releases_Grand_Central_Dispatch_as_Open_Source" rel="nofollow">http:&#x2F;&#x2F;www.osnews.com&#x2F;story&#x2F;22152&#x2F;Apple_Releases_Grand_Centr...</a>