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diff --git a/static/freebsd/man7/c.7 3.html b/static/freebsd/man7/c.7 3.html new file mode 100644 index 00000000..98bbcb70 --- /dev/null +++ b/static/freebsd/man7/c.7 3.html @@ -0,0 +1,363 @@ +<table class="head"> + <tr> + <td class="head-ltitle">C(7)</td> + <td class="head-vol">Miscellaneous Information Manual</td> + <td class="head-rtitle">C(7)</td> + </tr> +</table> +<div class="manual-text"> +<section class="Sh"> +<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1> +<p class="Pp"><code class="Nm">c</code>, <code class="Nm">c78</code>, + <code class="Nm">c89</code>, <code class="Nm">c90</code>, + <code class="Nm">c95</code>, <code class="Nm">c99</code>, + <code class="Nm">c11</code>, <code class="Nm">c17</code>, + <code class="Nm">c23</code>, <code class="Nm">c2y</code> — + <span class="Nd">The C programming language</span></p> +</section> +<section class="Sh"> +<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1> +<p class="Pp">C is a general purpose programming language, which has a strong + connection with the UNIX operating system and its derivatives, since the + vast majority of those systems were written in the C language. The C + language contains some basic ideas from the BCPL language through the B + language written by Ken Thompson in 1970 for the DEC PDP-7 machines. The + development of the UNIX operating system was started on a PDP-7 machine in + assembly language, but it made very difficult to port the existing code to + other systems.</p> +<p class="Pp">In 1972 Dennis M. Ritchie worked out the C programming language + for further development of the UNIX operating system. The idea was to + implement only the C compiler for different platforms, and implement most + part of the operating system in the new programming language to simplify the + portability between different architectures. It follows that C is very + eligible for (but not limited to) writing operating systems and low-level + applications.</p> +<p class="Pp">The C language did not have a specification or standardized + version for a long time. It went through a lot of changes and improvements + for ages. In 1978, Brian W. Kernighan and Dennis M. Ritchie published the + first book about C under the title "The C Programming Language". + We can think of this book as the first specification of the language. This + version is often referred as K&R C after the names of the authors. + Sometimes it is referred as C78, as well, after the publishing year of the + first edition of the book.</p> +<p class="Pp">It is important to notice, that the instruction set of the + language is limited to the most fundamental elements for simplicity. + Handling of the standard I/O and such common functions are implemented in + the libraries shipped with the compiler. As these functions are also widely + used, it was demanded to include into the description what requisites the + library should conform to, not just strictly the language itself. + Accordingly, the aforementioned standards cover the library elements, as + well. The elements of this standard library is still not enough for more + complicated tasks. In this case the provided system calls of the given + operating system can be used. To not lose the portability by using these + system calls, the POSIX (Portable Operating System Interface) standard + evolved. It describes what functions should be available to keep + portability. Note, that POSIX is not a C standard, but an operating system + standard and thus is beyond the scope of this manual. The standards + discussed below are all C standards and only cover the C programming + language and the accompanying library. All listed improvements for each + standard edition are taken from the official standard drafts. For further + details, check the publicly available drafts or purchase the published + standards — from either ISO or IEC resources.</p> +<p class="Pp">After the publication of the book mentioned before, the American + National Standards Institute (ANSI) started to work on standardizing the + language, and they announced ANSI X3.159-1989 in 1989. It is usually + referred to as ANSI C or C89. The main difference in this standard were the + function prototypes, which is a new way of declaring functions. With the + old-style function declarations, the compiler was unable to check the sanity + of the actual parameters at a function call. The old syntax was highly + error-prone because incompatible parameters were hard to detect in the + program code and the problem only showed up at run-time.</p> +<p class="Pp">In 1990, the International Organization for Standardization (ISO) + adopted the ANSI standard as ISO/IEC 9899:1990 in 1990. This is also + referred to as ISO C or C90. It only contains negligible minor modifications + against ANSI C, so the two standards often considered to be fully + equivalent. This was a very important milestone in the history of the C + language, but the development of the language did not stop.</p> +<p class="Pp">The ISO C standard was later extended with an amendment as ISO/IEC + 9899/AMD1 in 1995. This contained, for example, the wide-character support + in <code class="In"><<a class="In">wchar.h</a>></code> and + <code class="In"><<a class="In">wctype.h</a>></code>, and also + restricted character set support via diagraphs and + <code class="In"><<a class="In">iso646.h</a>></code>. This amendment + is usually referred to as C95. Two technical corrigenda were also published: + Technical Corrigendum 1 as ISO/IEC 9899/COR1 in 1994 and Technical + Corrigendum 2 as ISO/IEC 9899/COR2 in 1996. The continuous development and + growth made it necessary to work out a new standard, which contains the new + features and fixes the known defects and deficiencies of the language. As a + result, ISO/IEC 9899:1999 was born in 1999 as the second edition of the + standard. Similarly to the other standards, this is informally named after + the publication year as C99. The improvements include (but are not limited + to) the following:</p> +<ul class="Bl-bullet Bd-indent"> + <li>digraphs, trigraphs, and alternative spellings for the operators that use + non-ISO646 characters in + <code class="In"><<a class="In">iso646.h</a>></code></li> + <li>extended multibyte and wide character library support in + <code class="In"><<a class="In">wchar.h</a>></code> and + <code class="In"><<a class="In">wctype.h</a>></code></li> + <li>variable length arrays</li> + <li>flexible array members</li> + <li>complex (and imaginary) number arithmetic support in + <code class="In"><<a class="In">complex.h</a>></code></li> + <li>type-generic math macros in + <code class="In"><<a class="In">tgmath.h</a>></code></li> + <li>the long long int type and library functions</li> + <li>remove implicit int type</li> + <li>universal character names (\u and \U)</li> + <li>compound literals</li> + <li>remove implicit function declaration</li> + <li>BCPL style single-line comments</li> + <li>allow mixed declarations and code</li> + <li id="vscanf">the + <a class="permalink" href="#vscanf"><code class="Fn">vscanf</code></a>() + family of functions in + <code class="In"><<a class="In">stdio.h</a>></code> and + <code class="In"><<a class="In">wchar.h</a>></code></li> + <li>allow trailing comma in enum declaration</li> + <li>inline functions</li> + <li id="snprintf">the + <a class="permalink" href="#snprintf"><code class="Fn">snprintf</code></a>() + family of functions in + <code class="In"><<a class="In">stdio.h</a>></code></li> + <li>boolean type and macros in + <code class="In"><<a class="In">stdbool.h</a>></code></li> + <li>empty macro arguments</li> + <li>_Pragma preprocessing operator</li> + <li>__func__ predefined identifier</li> + <li>va_copy macro in + <code class="In"><<a class="In">stdarg.h</a>></code></li> + <li>additional strftime conversion specifiers</li> +</ul> +<p class="Pp">Later in 2011, the third edition of the standard, ISO/IEC + 1989:2011, commonly referred to as C11 (formerly C1x), came out and replaced + the second edition by ISO/IEC 9899:1999/COR1:2001, ISO/IEC + 9899:1999/COR2:2004, and ISO/IEC 9899:1999/COR3:2007. The improvements + include (but are not limited to) the following:</p> +<ul class="Bl-bullet Bd-indent"> + <li>support for multiple threads of execution and atomic operations in + <code class="In"><<a class="In">threads.h</a>></code> and + <code class="In"><<a class="In">stdatomic.h</a>></code></li> + <li>additional floating-point characteristic macros in + <code class="In"><<a class="In">float.h</a>></code></li> + <li>querying and specifying alignment of objects in + <code class="In"><<a class="In">stdalign.h</a>></code> and + <code class="In"><<a class="In">stdlib.h</a>></code></li> + <li>Unicode character types and functions in + <code class="In"><<a class="In">uchar.h</a>></code></li> + <li>type-generic expressions</li> + <li>static assertions in + <code class="In"><<a class="In">assert.h</a>></code></li> + <li>anonymous structures and unions</li> + <li>remove the gets function from + <code class="In"><<a class="In">stdio.h</a>></code></li> + <li>add the aligned_alloc, at_quick_exit, and quick_exit functions in + <code class="In"><<a class="In">stdlib.h</a>></code></li> +</ul> +<p class="Pp">C11 was later superseded by ISO/IEC 9899:2018, also known as C17 + which was prepared in 2017 and published in June 2018 as the fourth edition. + It incorporates the Technical Corrigendum 1 (ISO/IEC 9899:2011/COR1:2012) + which was published in 2012. It addressed defects and deficiencies in C11 + without introducing new features, only corrections and clarifications.</p> +<p class="Pp">C23, formally ISO/IEC 9899:2024, is the current standard with + significant updates that supersede C17 (ISO/IEC 9899:2018). The + standardization effort began in 2016, informally as C2x, with the first WG14 + meeting in 2019, and was officially published on October 31, 2024. C23 was + originally anticipated for an earlier release, but the timeline was extended + due to COVID-19 pandemic. With C23, the value of __STDC_VERSION__ has been + updated from 201710L to 202311L. Key changes include (but are not limited + to) the following:</p> +<ul class="Bl-bullet Bd-indent"> + <li>Add null pointer type nullptr_t and the nullptr keyword</li> + <li>Add constexpr keyword as a storage-class specifier for objects</li> + <li>Redefine the usage of the auto keyword to support type inference while + also retaining its previous functionality as a storage-class specifier + when used with a type</li> + <li id="printf">Add %b binary conversion specifier to the + <a class="permalink" href="#printf"><code class="Fn">printf</code></a>() + and + <a class="permalink" href="#scanf"><code class="Fn" id="scanf">scanf</code></a>() + function families</li> + <li id="strtol">Add binary conversion support (0b and 0B) to the + <a class="permalink" href="#strtol"><code class="Fn">strtol</code></a>() + and + <a class="permalink" href="#wcstol"><code class="Fn" id="wcstol">wcstol</code></a>() + function families</li> + <li>Add the #embed directive for binary resource inclusion and __has_embed to + check resource availability with preprocessor directives</li> + <li>Add the #warning directive for diagnostics</li> + <li>Add the #elifdef and #elifndef directives</li> + <li>Add the u8 prefix for character literals to represent UTF-8 encoding, + compatible with C++17</li> + <li>Add the char8_t type for UTF-8 encoded data and update the types of u8 + character constants and string literals to char8_t</li> + <li id="mbrtoc8">Add functions + <a class="permalink" href="#mbrtoc8"><code class="Fn">mbrtoc8</code></a>() + and + <a class="permalink" href="#c8rtomb"><code class="Fn" id="c8rtomb">c8rtomb</code></a>() + to convert between narrow multibyte characters and UTF-8 encoding</li> + <li>Define all char16_t strings and literals as UTF-16 encoded and char32_t + strings and literals as UTF-32 encoded unless specified otherwise</li> + <li>Allow storage-class specifiers within compound literals</li> + <li>Support the latest IEEE 754 standard, ISO/IEC 60559:2020, with binary and + (optional) decimal floating-point arithmetic</li> + <li>Add single-argument _Static_assert for compatibility with C++17</li> + <li>Add _Decimal32, _Decimal64, _Decimal128 keywords for (optional) decimal + floating-point arithmetic</li> + <li>Add digit separator ' (the single quote character) for literals</li> + <li>Enable specification of the underlying type of an enum</li> + <li id="typeof">Standardize the + <a class="permalink" href="#typeof"><code class="Fn">typeof</code></a>() + operator</li> + <li id="memset_explicit">Add + <a class="permalink" href="#memset_explicit"><code class="Fn">memset_explicit</code></a>() + in <code class="In"><<a class="In">string.h</a>></code> to securely + erase sensitive data regardless of optimizations</li> + <li id="memccpy">Add + <a class="permalink" href="#memccpy"><code class="Fn">memccpy</code></a>() + in <code class="In"><<a class="In">string.h</a>></code> for + efficient string concatenation</li> + <li id="memalignment">Add + <a class="permalink" href="#memalignment"><code class="Fn">memalignment</code></a>() + in <code class="In"><<a class="In">stdlib.h</a>></code> to determine + pointer alignment</li> + <li id="strdup">Add + <a class="permalink" href="#strdup"><code class="Fn">strdup</code></a>() + and + <a class="permalink" href="#strndup"><code class="Fn" id="strndup">strndup</code></a>() + in <code class="In"><<a class="In">string.h</a>></code> to allocate + string copies</li> + <li>Introduce bit utility functions, macros, and types in the new header + <code class="In"><<a class="In">stdbit.h</a>></code></li> + <li id="timegm">Add + <a class="permalink" href="#timegm"><code class="Fn">timegm</code></a>() + in <code class="In"><<a class="In">time.h</a>></code> for converting + time structures to calendar time values</li> + <li>Add __has_include for header availability checking via preprocessor + directives</li> + <li>Add __has_c_attribute to check attribute availability via preprocessor + directives</li> + <li>Add _BitInt(N) and unsigned _BitInt(N) for bit-precise integers, and + BITINT_MAXWIDTH for maximum bit width</li> + <li>Elevate true and false to proper keywords (previously macros from + <code class="In"><<a class="In">stdbool.h</a>></code>)</li> + <li>Add keywords alignas, alignof, bool, static_assert, thread_local; + previously defined keywords remain available as alternative spellings</li> + <li>Enable zero initialization with {} (including initialization of VLAs)</li> + <li>Introduce C++11 style attributes using [[]], with adding [[deprecated]], + [[fallthrough]], [[maybe_unused]], [[nodiscard]], and [[noreturn]]</li> + <li>Deprecate _Noreturn, noreturn, header + <code class="In"><<a class="In">stdnoreturn.h</a>></code> features + introduced in C11</li> + <li>Remove trigraph support</li> + <li>Remove K&R function definitions and declarations</li> + <li>Remove non-two's-complement representations for signed integers</li> +</ul> +<p class="Pp">The next version of the C Standard, informally named C2y, is + anticipated to release within the next six years, targeting 2030 at the + latest. A charter for C2y is still being drafted and discussed, with several + papers under debate from the January 2024 meeting in Strasbourg, France + indicating that this new version may address long-standing requests and + deficiencies noted by the C community, while preserving its core + strengths.</p> +<p class="Pp">ISO/IEC JTC1/SC22/WG14 committee is responsible for the ISO/IEC + 9899, C Standard.</p> +</section> +<section class="Sh"> +<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE + ALSO</a></h1> +<p class="Pp"><a class="Xr">c89(1)</a>, <a class="Xr">c99(1)</a>, + <a class="Xr">cc(1)</a></p> +</section> +<section class="Sh"> +<h1 class="Sh" id="STANDARDS"><a class="permalink" href="#STANDARDS">STANDARDS</a></h1> +<p class="Pp"><cite class="Rs"><span class="RsA">ANSI</span>, + <span class="RsT">X3.159-1989 (aka C89 or ANSI C)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">9899:1990 (aka C90)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">9899:1990/AMD 1:1995, Amendment 1: C Integrity (aka + C95)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">9899:1990/COR 1:1994, Technical Corrigendum + 1</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">9899:1990/COR 2:1996, Technical Corrigendum + 2</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">9899:1999 (aka C99)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">9899:1999/COR 1:2001, Technical Corrigendum + 1</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">9899:1999/COR 2:2004, Technical Corrigendum + 2</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">9899:1999/COR 3:2007, Technical Corrigendum + 3</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">TR 24731-1:2007 (aka bounds-checking + interfaces)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">TS 18037:2008 (aka, embedded C)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">TR 24747:2009 (aka mathematical special + functions)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">TR 24732:2009 (aka decimal + floating-point)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">TR 24731-2:2010 (aka dynamic allocation + functions)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">9899:2011 (aka C11)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">9899:2011/COR 1:2012, Technical Corrigendum + 1</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">TS 17961:2013 (aka C secure coding + rules)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">TS 18861-1:2014 (aka binary + floating-point)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">TS 18861-2:2015 (aka decimal + floating-point)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">TS 18861-3:2015 (aka interchange and extended + types)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">TS 18861-4:2015 (aka supplementary + functions)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">TS 17961:2013/COR 1:2016 (aka C secure coding rules + TC1)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">TS 18861-5:2016 (aka supplementary + attributes)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">9899:2018 (aka C17)</span>.</cite></p> +<p class="Pp"><cite class="Rs"><span class="RsA">ISO/IEC</span>, + <span class="RsT">9899:2024 (aka C23)</span>.</cite></p> +</section> +<section class="Sh"> +<h1 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h1> +<p class="Pp">This manual page first appeared in <span class="Ux">FreeBSD + 9.0</span>.</p> +</section> +<section class="Sh"> +<h1 class="Sh" id="AUTHORS"><a class="permalink" href="#AUTHORS">AUTHORS</a></h1> +<p class="Pp">This manual page was originally written by <span class="An">Gabor + Kovesdan</span> + <<a class="Mt" href="mailto:gabor@FreeBSD.org">gabor@FreeBSD.org</a>>. + It was updated by <span class="An">Faraz Vahedi</span> + <<a class="Mt" href="mailto:kfv@kfv.io">kfv@kfv.io</a>> with + information about more recent C standards.</p> +</section> +</div> +<table class="foot"> + <tr> + <td class="foot-date">November 4, 2024</td> + <td class="foot-os">FreeBSD 15.0</td> + </tr> +</table> |