History of C

Early C

  • 1969: B created, based on BCPL, to replace PDP-7 assembler as the system programming language for Unix
    • added operators ++, --, compound assignment, remained a typeless language like BCPL
  • 1971: NB ("new B") created when porting B to PDP-11
    • types (int, char, arrays and pointers), array-to-pointer conversion, compilation to machine code
  • 1972: Language renamed to C
    • struct, operators && and ||, preprocessor, portable I/O
  • 1973: Unix re-written in C
    • unsigned, long, union, enumerations, increased type safety
  • 1978: The C Programming Language, 1st edition

Standard C

  • 1983: ANSI established X3J11 committee
  • 1988: The C Programming Language, 2nd edition
  • 1989: C89, the ANSI C standard published
  1. codified existing practices
  2. new features: volatile, enum, signed, void, locales
  3. From C++: const, function prototypes
  • 1990: C90, the ANSI C standard accepted as ISO/IEC 9899:1990
  • 1994: Technical corrigendum 1 (ISO/IEC 9899:1990/Cor.1:1994)
  • 1995: C95 (ISO/IEC 9899:1990/Amd.1:1995) (online store)
  1. greatly expanded wide and multibyte character support (<wctype.h>, <wchar.h>, additions and changes to stream I/O, etc)
  2. digraphs, <iso646.h>,
  • 1996: Technical corrigendum 2 (ISO/IEC 9899:1990/Cor.2:1996)
  • 1999: C99 (ISO/IEC 9899:1999)
  1. new features: bool, long long, <stdint.h>, <inttypes.h>, restrict, compound literals, variable length arrays, flexible array members, designated initializers, <fenv.h>, variadic macros, complex numbers, __func__, hexadecimal floating point format (%a), monetary formatting in lconv, isblank, concatenation of narrow and wide string literals, trailing comma in enumerations, empty arguments in function-like macros, STDC_* pragmas, va_copy, null return of tmpnam, null pointer in setvbuf, hh and ll length-specifiers in printf, snprintf, _Exit, <tgmath.h>, POSIX-like strftime specifiers
  2. from C++: inline, mix declarations and code, declarations in the init-clause of the for loop, // comments, universal character names in source code
  3. removed implicit functions and implicit int
  • 2001: Technical corrigendum 1 (ISO/IEC 9899:1999/Cor.1:2001)
  • 2004: Technical corrigendum 2 (ISO/IEC 9899:1999/Cor.2:2004)
  • 2004: Unicode TR (ISO/IEC TR 19769:2004) (ISO store) (N1040 November 7, 2003 draft)
  • 2007: Technical corrigendum 3 (ISO/IEC 9899:1999/Cor.3:2007) (N1256 September 7, 2007 draft)
  • 2007: Bounds-checking interfaces TR (ISO/IEC TR 24731-1:2007) (ISO store) (N1225 March 28, 2007 draft)
  • 2008: Embedded TR (ISO/IEC TR 18037:2008) (ISO store) (N1021 September 24, 2003 draft)
  • 2009: Decimal floating-point TR (ISO/IEC TR 24732:2009) (ISO store) (N1241 July 5, 2007 draft)
  • 2009: Mathematical special functions TR (ISO/IEC TR 24747:2009) (ISO store) (N1182 August 2, 2006 draft)
  • 2010: Dynamic allocations functions TR (ISO/IEC TR 24731-2:2010) (ISO store) (N1388 June 1, 2009 draft)
  • 2011: C11 (ISO/IEC 9899:2011) (ISO store) (ANSI store) (N1570 April 12, 2011 draft)
  1. thread-aware memory model, <stdatomic.h>, <threads.h>, type-generic functions, alignas/alignof, noreturn, static_assert, analyzability extensions, extensions to complex and imaginary types, anonymous structures and unions, exclusive file open mode, quick_exit
  2. removed gets
  3. from Bounds-checking interfaces TR: bounds-checking interfaces,
  4. from Unicode TR: char16_t, char32_t, and <uchar.h>
  • 2012: Technical corrigendum 1 (ISO/IEC 9899:2011/Cor 1:2012) (ISO store)
  • 2013: Secure Coding Rules TS (ISO/IEC TS 17961:2013) (ISO store) (N1718 May 30, 2013)
  • 2014: FP TS part 1: Binary floating-point arithmetic (ISO/IEC TS 18661-1:2014) (ISO store) (N1778 2013 draft)
  1. provides changes to C11 (mostly to Annex F) that cover all basic requirements and some recommendations of IEC 60559:2011 (C11 was built on IEC 60559:1989)
  • 2015: FP TS part 2: Decimal floating-point arithmetic (ISO/IEC TS 18661-2:2015) (ISO store) (N1912 2015 draft)
  1. provides changes to C11 to support all the requirements, plus some basic recommendations, of IEC 60559:2011 for decimal floating-point arithmetic. This supersedes ISO/IEC TR 24732:2009.
  • 2015: FP TS part 3: Interchange and extended types (ISO/IEC TS 18661-3:2015) (ISO store) (N1945 2015 draft)
  1. provides changes to C11 to support the recommendations of IEC 60559:2011 for extended floating‐point formats and the interchange formats, both arithmetic and non-arithmetic.
  • 2015: FP TS part 4: Supplementary functions (ISO/IEC TS 18661-4:2015) (ISO store) (N1950 2015 draft)
  1. provides changes to C11 to support all mathematical operations recommended by IEC 60559:2011, including trigonometry in π units, inverse square root, compounded interest, etc.
  • 2016: FP TS part 5: Supplementary attributes (ISO/IEC TS 18661-5:2016) (ISO store) (N2004 2016 draft)
  1. provides changes to C11 to support all supplementary attributes (evaluation model, exception handling, reproducibility, etc) recommended by IEC 60559:2011
Main Article: C17
Defect Reports fixed in C17 (54 defects)

Future development

  • Parallelism TS (Draft N2017 2016-03-10)
  • Transactional Memory TS (Draft N1961 2015-09-23)
  • C23 (Latest draft n3054 2022-09-03)
  1. List of issues that were not granted DR status: (N2556 2020-08-02)
Main Article: C23
Next major C language standard revision
Defect Reports fixed in C23 (? defects)

See also

C++ documentation for History of C++

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