K&R C

updated 2022-05-29

The C Programming Language, 1st ed. (The Internet Archive)
C Reference Manual (this paper bears striking similarity to and was also written by the author of Appendix A of The C Programming Language, 1st ed. - the chronology of these writings' release is unknown)
"A damn stupid thing to do" - the origins of C
The Development of the C Language
PDP-11 Emulator

The C programming language was first described to the public in The C Programming Language by Brian W. Kernighan and Dennis M. Ritchie, published by Prentice Hall in 1978. The language evolved out of the former B programming language, which was a product of Ken Thompson:

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Challenged by McIlroy's feat in reproducing TMG, Thompson decided that Unix—possibly it had not even been named yet—needed a system programming language. After a rapidly scuttled attempt at Fortran, he created instead a language of his own, which he called B. B can be thought of as C without types; more accurately, it is BCPL squeezed into 8K bytes of memory and filtered through Thompson's brain. Its name most probably represents a contraction of BCPL, though an alternate theory holds that it derives from Bon [Thompson 69], an unrelated language created by Thompson during the Multics days. Bon in turn was named either after his wife Bonnie, or (according to an encyclopedia quotation in its manual), after a religion whose rituals involve the murmuring of magic formulas.

""" (The Development of the C Language)

[Thompson 69] references K. Thompson, `Bon—an Interactive Language,' undated AT&T Bell Laboratories internal memorandum (ca. 1969). This is possibly Bon User's Manual. Please get in touch if you have a hyperlink for this document as I can't find it indexed on any search engines.

This language described in The C Programming Language isn't the C programming language known by most. It was a pre-standardization, relatively prototypical C, and rather than being codified in ANSI its primary documentation was the book by Kernighan and Ritchie (this book would later be known colloquially as K&R). This was known as "pre-ANSI C" or "K&R C" and dubbed "C78" for the purposes of naming this page, in the same style as the later "C89", described in ANSI X3.159-1989, or "C11", described in ISO/IEC 9899:2011. "C78" was also the name given to historical C by the c78(7) manual page on FreeBSD 9.0.

"C78" is incompatible with "C89" and later standards. This page documents those incompatibilities and relative oddities.

I have never done (and probably never will do) extensive programming in pre-ANSI C. These incompatibilities were discovered out of Appendix C in The C Programming Language, 2nd ed. but are described further.