semex is a tester and exerciser for Unix System V semaphore functions. It is quite useful for getting hands-on knowledge of them, and also as a part of a test frame for any semaphore-using program.
Open source project that offer summary and download services on this page is a project that carry out their development work on other open source development sites. Their work is linked to this page via a feature called OFI, and their work is not carried out here on OSDN site.