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26 <div class="titlepage"><div><div><h4 class="title">
27 <a name="beast.ref.boost__beast__http__is_fields"></a><a class="link" href="boost__beast__http__is_fields.html" title="http::is_fields">http::is_fields</a>
28 </h4></div></div></div>
30 <a class="indexterm" name="idm45873496785728"></a>
31 Determine if a type meets the <span class="emphasis"><em>Fields</em></span>
35 <a name="beast.ref.boost__beast__http__is_fields.h0"></a>
36 <span class="phrase"><a name="beast.ref.boost__beast__http__is_fields.synopsis"></a></span><a class="link" href="boost__beast__http__is_fields.html#beast.ref.boost__beast__http__is_fields.synopsis">Synopsis</a>
39 Defined in header <code class="literal"><<a href="../../../../../../boost/beast/http/type_traits.hpp" target="_top">boost/beast/http/type_traits.hpp</a>></code>
41 <pre class="programlisting"><span class="keyword">template</span><span class="special"><</span>
42 <span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span>
43 <span class="keyword">using</span> <span class="identifier">is_fields</span> <span class="special">=</span> <span class="emphasis"><em>see-below</em></span><span class="special">;</span>
46 <a name="beast.ref.boost__beast__http__is_fields.h1"></a>
47 <span class="phrase"><a name="beast.ref.boost__beast__http__is_fields.description"></a></span><a class="link" href="boost__beast__http__is_fields.html#beast.ref.boost__beast__http__is_fields.description">Description</a>
50 This alias template is <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">true_type</span></code>
51 if <code class="computeroutput"><span class="identifier">T</span></code> meets the requirements,
52 otherwise it is <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">false_type</span></code>.
55 <a name="beast.ref.boost__beast__http__is_fields.h2"></a>
56 <span class="phrase"><a name="beast.ref.boost__beast__http__is_fields.template_parameters"></a></span><a class="link" href="boost__beast__http__is_fields.html#beast.ref.boost__beast__http__is_fields.template_parameters">Template
59 <div class="informaltable"><table class="table">
79 <code class="computeroutput"><span class="identifier">T</span></code>
90 <a name="beast.ref.boost__beast__http__is_fields.h3"></a>
91 <span class="phrase"><a name="beast.ref.boost__beast__http__is_fields.example"></a></span><a class="link" href="boost__beast__http__is_fields.html#beast.ref.boost__beast__http__is_fields.example">Example</a>
94 Use with <code class="computeroutput"><span class="keyword">static_assert</span></code>:
96 <pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">bool</span> <span class="identifier">isRequest</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Body</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Fields</span><span class="special">></span>
97 <span class="keyword">void</span> <span class="identifier">f</span><span class="special">(</span><span class="identifier">message</span><span class="special"><</span><span class="identifier">isRequest</span><span class="special">,</span> <span class="identifier">Body</span><span class="special">,</span> <span class="identifier">Fields</span><span class="special">></span> <span class="keyword">const</span><span class="special">&)</span>
98 <span class="special">{</span>
99 <span class="keyword">static_assert</span><span class="special">(</span><span class="identifier">is_fields</span><span class="special"><</span><span class="identifier">Fields</span><span class="special">>::</span><span class="identifier">value</span><span class="special">,</span>
100 <span class="string">"Fields type requirements not met"</span><span class="special">);</span>
101 <span class="special">...</span>
104 Use with <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">enable_if</span></code> (SFINAE):
106 <pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">bool</span> <span class="identifier">isRequest</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Body</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Fields</span><span class="special">></span>
107 <span class="keyword">typename</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">enable_if</span><span class="special"><</span><span class="identifier">is_fields</span><span class="special"><</span><span class="identifier">Fields</span><span class="special">>::</span><span class="identifier">value</span><span class="special">>::</span><span class="identifier">type</span>
108 <span class="identifier">f</span><span class="special">(</span><span class="identifier">message</span><span class="special"><</span><span class="identifier">isRequest</span><span class="special">,</span> <span class="identifier">Body</span><span class="special">,</span> <span class="identifier">Fields</span><span class="special">></span> <span class="keyword">const</span><span class="special">&);</span>
111 Convenience header <code class="literal"><<a href="../../../../../../boost/beast/http.hpp" target="_top">boost/beast/http.hpp</a>></code>
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