The language was originally designed in the 1970s at Bell Labs and was used as the implementation language for the UNIX operating system. Probably the most widely used reference is The C Programming Language by Kernighan and Ritchie, although an ANSI/ISO standard became available in 1989.

The C language has a reputation for predictable performance, making it possible to create high-performance applications. Unfortunately, it also makes it very easy to introduce subtle bugs, which can often be exploited as security holes in internet applications.