The UNIX system: The evolution of C — Past and future

The C programming language was developed originally to implement UNIX™ operating systems and their utilities. It has become a mainstay of systems and application programming at AT&T Bell Laboratories, and is rapidly growing in commercial importance. It continues to evolve in response to the needs of new environments, spanning the range from tiny peripheral controllers to huge electronic switching systems written and maintained by hundreds of programmers. There are severe reliability and real-time constraints throughout this spectrum. This paper reports changes made so far to meet the needs of these new environments and indicates the directions of current developments.