Editing c/c99

'''C99''' is a past version of the [[C programming language]] standard which was ratified by ISO in 1999 and became '''ISO/IEC 9899:1999'''. The same standard was later also adopted by ANSI on May 22, 2000. C99 cancels and replaces the first edition, [[C89]], and [[Normative Addendum 1|NA1]].

C99 brought the first major updates to the language in a decade. The new standard introduced restricted pointers, variable-length arrays, flexible array members, complex numbers support, type-generic math, <code>long long int</code>, extended identifiers, hexadecimal floating-point constants, compound literals, designated initializers, single line, <code>//</code> comments, extended integer type, the ability to mix declarations and code, variadic macros, new math functions, inline functions, boolean types, _Pragma and standard pragmas, and VA_COPY. The standard also removed implicit function declaration.

== Version detection ==
C99 can be detected via the __STDC_VERSION__ mandatory macro which must equal <code>199901L</code>. 

<source lang="C">
#if __STDC_VERSION__ >= 199901L
    /* C99 support */
#endif
</source>

== New headers ==
C99 introduced 6 new [[C standard library|standard headers]]: [[tgmath.h - C|<tgmath.h>]], [[stdint.h - C|<stdint.h>]], [[stdbool.h - C|<stdbool.h>]], [[inttypes.h - C|<inttypes.h>]], [[fenv.h - C|<fenv.h>]], and [[complex.h - C|<complex.h>]].

== Compiler support ==
Support for C99 has been a slow ongoing effort.

{| class="wikitable"
|-
| style="background:#CCCCFF;text-align:center;" colspan="4" | C99 Compiler Support
|-
! Compiler Name !! Support Level !! style="text-align:center;" | Enforcement Switch !! Note
|-
| ACK || style="background:#FF6666;text-align:center;" | No Support || ||
|-
| Clang || style="background:#99FF66;text-align:center;" | Complete || style="text-align:center;" | -std=c99 || No extended identifier support<ref>[http://p99.gforge.inria.fr/c99-conformance/c99-conformance-clang-3.2.html C99 Conformance CLANG Test]</ref>
|-
| GCC || style="background:#99FF66;text-align:center;" | Complete || style="text-align:center;" | -std=c99 || Supports everything<ref>[http://p99.gforge.inria.fr/c99-conformance/c99-conformance-gcc-4.7.html C99 Conformance GCC Test]</ref>
|-
| TCC || style="background:#FFCC66;text-align:center;" | Partial || || Missing lots of features<ref>[http://p99.gforge.inria.fr/c99-conformance/c99-conformance-tcc-0.9.25.html C99 Conformance TCC Test]</ref>
|-
| ICC || style="background:#FFCC66;text-align:center;" | Partial || style="text-align:center;" | -std=c99 || Broken extended identifier support, broken inline function support<ref>[http://p99.gforge.inria.fr/c99-conformance/c99-conformance-icc-12.0.0.html C99 Conformance ICC Test]</ref>
|-
| Visual C++ || style="background:#FFCC66;text-align:center;" | Partial ||   || Missing type-generic math<ref>[http://blogs.msdn.com/b/vcblog/archive/2013/07/19/c99-library-support-in-visual-studio-2013.aspx C99 library support in Visual Studio 2013]</ref>
|}

== References ==
{{reflist}}