diff options
Diffstat (limited to 'devdocs/c/language%2F_alignof.html')
| -rw-r--r-- | devdocs/c/language%2F_alignof.html | 51 |
1 files changed, 0 insertions, 51 deletions
diff --git a/devdocs/c/language%2F_alignof.html b/devdocs/c/language%2F_alignof.html deleted file mode 100644 index 1a478589..00000000 --- a/devdocs/c/language%2F_alignof.html +++ /dev/null @@ -1,51 +0,0 @@ - <h1 id="firstHeading" class="firstHeading">_Alignof operator <span class="t-mark-rev t-since-c11">(since C11)</span> -</h1> <p>Queries the alignment requirement of its operand type.</p> -<h3 id="Syntax"> Syntax</h3> <table class="t-sdsc-begin"> <tr class="t-sdsc"> <td> <code>_Alignof(</code> <span class="t-spar">type-name</span> <code>)</code> </td> <td class="t-sdsc-nopad"> </td> <td> <span class="t-mark-rev t-since-c11">(since C11)</span> </td> -</tr> <tr class="t-sdsc"> <td> <code>alignof(</code> <span class="t-spar">type-name</span> <code>)</code> </td> <td class="t-sdsc-nopad"> </td> <td> <span class="t-mark-rev t-since-c23">(since C23)</span> </td> -</tr> -</table> <table class="t-rev-begin"> <tr class="t-rev t-until-c23"> -<td> <p>This operator is typically used through the convenience macro <a href="../types" title="c/types"><code>alignof</code></a>, which is provided in the header <a href="../types" title="c/types"><code><stdalign.h></code></a></p> -</td> <td><span class="t-mark-rev t-until-c23">(until C23)</span></td> -</tr> </table> <h3 id="Explanation"> Explanation</h3> <p>Returns the <a href="object#Alignment" title="c/language/object">alignment requirement</a> of the type <a href="type#Type_names" title="c/language/type">named</a> by <span class="t-spar">type-name</span>. If <span class="t-spar">type-name</span> is an array type, the result is the alignment requirement of the array element type. The <span class="t-spar">type-name</span> cannot be function type or an incomplete type.</p> -<p>The result is an integer constant of type <code><a href="../types/size_t" title="c/types/size t">size_t</a></code>.</p> -<p>The operand is not evaluated (so external identifiers used in the operand do not have to be defined).</p> -<p>If <span class="t-spar">type-name</span> is a <a href="array" title="c/language/array">VLA</a> type, its size expression is not evaluated.</p> -<h3 id="Notes"> Notes</h3> <p>The use of <span class="t-rev-inl t-until-c23"><span><code>_Alignof</code></span><span><span class="t-mark-rev t-until-c23">(until C23)</span></span></span><span class="t-rev-inl t-since-c23"><span><code>alignof</code></span><span><span class="t-mark-rev t-since-c23">(since C23)</span></span></span> with expressions is allowed by some C compilers as a non-standard extension.</p> -<h3 id="Keywords"> Keywords</h3> <p><a href="../keyword/alignof" title="c/keyword/alignof"><code>alignof</code></a>, <a href="../keyword/_alignof" title="c/keyword/ Alignof"><code>_Alignof</code></a></p> -<h3 id="Example"> Example</h3> <div class="t-example"> <div class="c source-c"><pre data-language="c">#include <stdalign.h> -#include <stddef.h> -#include <stdio.h> - -int main(void) -{ - printf("Alignment of char = %zu\n", alignof(char)); - printf("Alignment of max_align_t = %zu\n", alignof(max_align_t)); - printf("alignof(float[10]) = %zu\n", alignof(float[10])); - printf("alignof(struct{char c; int n;}) = %zu\n", - alignof(struct {char c; int n;})); -}</pre></div> <p>Possible output:</p> -<div class="text source-text"><pre data-language="c">Alignment of char = 1 -Alignment of max_align_t = 16 -alignof(float[10]) = 4 -alignof(struct{char c; int n;}) = 4</pre></div> </div> <h3 id="Defect_reports"> Defect reports</h3> <p>The following behavior-changing defect reports were applied retroactively to previously published C standards.</p> -<table class="dsctable"> <tr> <th>DR </th> <th>Applied to </th> <th>Behavior as published </th> <th>Correct behavior </th> -</tr> <tr> <td> -<a rel="nofollow" class="external text" href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2396.htm#dr_494">DR 494</a> </td> <td>C11 </td> <td>whether the size expression in a VLA is evaluated in <code>_Alignof</code> was unspecified </td> <td>it is unevaluated </td> -</tr> -</table> <h3 id="References"> References</h3> <ul> -<li> C23 standard (ISO/IEC 9899:2023): </li> -<ul><li> 6.5.3.4 The sizeof and alignof operators (p: TBD) </li></ul> -<li> C17 standard (ISO/IEC 9899:2018): </li> -<ul><li> 6.5.3.4 The sizeof and _Alignof operators (p: 64-65) </li></ul> -<li> C11 standard (ISO/IEC 9899:2011): </li> -<ul><li> 6.5.3.4 The sizeof and _Alignof operators (p: 90-91) </li></ul> -</ul> <h3 id="See_also"> See also</h3> <table class="t-dsc-begin"> <tr class="t-dsc"> <td> <div><a href="../types/max_align_t" title="c/types/max align t"> <span class="t-lines"><span>max_align_t</span></span></a></div> -<div><span class="t-lines"><span><span class="t-mark-rev t-since-c11">(C11)</span></span></span></div> </td> <td> a type with alignment requirement as great as any other scalar type <br> <span class="t-mark">(typedef)</span> </td> -</tr> <tr class="t-dsc"> <td> <a href="_alignas" title="c/language/ Alignas"><code>_Alignas</code> specifier</a><span class="t-mark-rev t-since-c11">(C11)</span> </td> <td> sets alignment requirements of an object </td> -</tr> <tr class="t-dsc"> <td colspan="2"> <span><a href="https://en.cppreference.com/w/cpp/language/alignof" title="cpp/language/alignof">C++ documentation</a></span> for <code>alignof operator</code> </td> -</tr> </table> <div class="_attribution"> - <p class="_attribution-p"> - © cppreference.com<br>Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.<br> - <a href="https://en.cppreference.com/w/c/language/_Alignof" class="_attribution-link">https://en.cppreference.com/w/c/language/_Alignof</a> - </p> -</div> |