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accesskey="n" href="quant_1_3_44_10_2_36_1_1_4.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 25</div> 26<div class="refentry"> 27<a name="boost.units.quantity"></a><div class="titlepage"></div> 28<div class="refnamediv"> 29<h2><span class="refentrytitle">Class template quantity</span></h2> 30<p>boost::units::quantity — class declaration </p> 31</div> 32<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> 33<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: <<a class="link" href="../../boost_units/Reference.html#header.boost.units.quantity_hpp" title="Header <boost/units/quantity.hpp>">boost/units/quantity.hpp</a>> 34 35</span><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Unit<span class="special">,</span> <span class="keyword">typename</span> Y<span class="special">></span> 36<span class="keyword">class</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a> <span class="special">{</span> 37<span class="keyword">public</span><span class="special">:</span> 38 <span class="comment">// types</span> 39 <span class="keyword">typedef</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit</span><span class="special">,</span> <span class="identifier">Y</span> <span class="special">></span> <a name="boost.units.quantity.this_type"></a><span class="identifier">this_type</span><span class="special">;</span> 40 <span class="keyword">typedef</span> <span class="identifier">Y</span> <a name="boost.units.quantity.value_type"></a><span class="identifier">value_type</span><span class="special">;</span> 41 <span class="keyword">typedef</span> <span class="identifier">Unit</span> <a name="boost.units.quantity.unit_type"></a><span class="identifier">unit_type</span><span class="special">;</span> 42 43 <span class="comment">// <a class="link" href="quantity.html#boost.units.quantityconstruct-copy-destruct">construct/copy/destruct</a></span> 44 <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_8-bb"><span class="identifier">quantity</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> 45 <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_9-bb"><span class="identifier">quantity</span></a><span class="special">(</span><span class="identifier">unspecified_null_pointer_constant_type</span><span class="special">)</span><span class="special">;</span> 46 <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_10-bb"><span class="identifier">quantity</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">this_type</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 47 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> YY<span class="special">></span> 48 <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_12-bb"><span class="identifier">quantity</span></a><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span><span class="special">,</span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span> <span class="special">=</span> <span class="number">0</span><span class="special">)</span><span class="special">;</span> 49 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> YY<span class="special">></span> 50 <span class="keyword">explicit</span> <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_13-bb"><span class="identifier">quantity</span></a><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span><span class="special">,</span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span> <span class="special">=</span> <span class="number">0</span><span class="special">)</span><span class="special">;</span> 51 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Unit2<span class="special">,</span> <span class="keyword">typename</span> YY<span class="special">></span> 52 <span class="keyword">explicit</span> <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_15-bb"><span class="identifier">quantity</span></a><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit2</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span><span class="special">,</span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span> <span class="special">=</span> <span class="number">0</span><span class="special">)</span><span class="special">;</span> 53 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Unit2<span class="special">,</span> <span class="keyword">typename</span> YY<span class="special">></span> 54 <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_16-bb"><span class="identifier">quantity</span></a><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit2</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span><span class="special">,</span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span> <span class="special">=</span> <span class="number">0</span><span class="special">)</span><span class="special">;</span> 55 <span class="keyword">explicit</span> <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_20-bb"><span class="identifier">quantity</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">value_type</span> <span class="special">&</span><span class="special">,</span> <span class="keyword">int</span><span class="special">)</span><span class="special">;</span> 56 <span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_11-bb"><span class="keyword">operator</span><span class="special">=</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">this_type</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 57 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> YY<span class="special">></span> 58 <span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_14-bb"><span class="keyword">operator</span><span class="special">=</span></a><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 59 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Unit2<span class="special">,</span> <span class="keyword">typename</span> YY<span class="special">></span> 60 <span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_17-bb"><span class="keyword">operator</span><span class="special">=</span></a><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit2</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 61 62 <span class="comment">// <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_6-bb">private member functions</a></span> 63 <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_6_1-bb"><span class="identifier">BOOST_MPL_ASSERT_NOT</span></a><span class="special">(</span><span class="emphasis"><em><span class="identifier">unspecified</span></em></span><span class="special">)</span><span class="special">;</span> 64 65 <span class="comment">// <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_7-bb">public member functions</a></span> 66 <span class="identifier">BOOST_CONSTEXPR</span> <span class="keyword">const</span> <span class="identifier">value_type</span> <span class="special">&</span> <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_7_1-bb"><span class="identifier">value</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 67 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Unit2<span class="special">,</span> <span class="keyword">typename</span> YY<span class="special">></span> 68 <span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> 69 <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_7_2-bb"><span class="keyword">operator</span><span class="special">+=</span></a><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit2</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 70 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Unit2<span class="special">,</span> <span class="keyword">typename</span> YY<span class="special">></span> 71 <span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> 72 <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_7_3-bb"><span class="keyword">operator</span><span class="special">-=</span></a><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit2</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 73 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Unit2<span class="special">,</span> <span class="keyword">typename</span> YY<span class="special">></span> 74 <span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> 75 <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_7_4-bb"><span class="keyword">operator</span> <span class="special">*=</span></a><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit2</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 76 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Unit2<span class="special">,</span> <span class="keyword">typename</span> YY<span class="special">></span> 77 <span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> 78 <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_7_5-bb"><span class="keyword">operator</span><span class="special">/=</span></a><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit2</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 79 <span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_7_6-bb"><span class="keyword">operator</span> <span class="special">*=</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">value_type</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 80 <span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_7_7-bb"><span class="keyword">operator</span><span class="special">/=</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">value_type</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 81 82 <span class="comment">// <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_18-bb">public static functions</a></span> 83 <span class="keyword">static</span> <span class="identifier">BOOST_CONSTEXPR</span> <span class="identifier">this_type</span> <a class="link" href="quantity.html#id-1_3_44_10_2_36_1_1_3_18_1-bb"><span class="identifier">from_value</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">value_type</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 84<span class="special">}</span><span class="special">;</span></pre></div> 85<div class="refsect1"> 86<a name="id-1.3.44.10.2.36.5.4"></a><h2>Description</h2> 87<div class="refsect2"> 88<a name="id-1.3.44.10.2.36.5.4.2"></a><h3> 89<a name="boost.units.quantityconstruct-copy-destruct"></a><code class="computeroutput">quantity</code> 90 public 91 construct/copy/destruct</h3> 92<div class="orderedlist"><ol class="orderedlist" type="1"> 93<li class="listitem"><pre class="literallayout"><a name="id-1_3_44_10_2_36_1_1_3_8-bb"></a><span class="identifier">quantity</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre></li> 94<li class="listitem"><pre class="literallayout"><a name="id-1_3_44_10_2_36_1_1_3_9-bb"></a><span class="identifier">quantity</span><span class="special">(</span><span class="identifier">unspecified_null_pointer_constant_type</span><span class="special">)</span><span class="special">;</span></pre></li> 95<li class="listitem"><pre class="literallayout"><a name="id-1_3_44_10_2_36_1_1_3_10-bb"></a><span class="identifier">quantity</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">this_type</span> <span class="special">&</span> source<span class="special">)</span><span class="special">;</span></pre></li> 96<li class="listitem"> 97<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> YY<span class="special">></span> 98 <a name="id-1_3_44_10_2_36_1_1_3_12-bb"></a><span class="identifier">quantity</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span> source<span class="special">,</span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span> <span class="special">=</span> <span class="number">0</span><span class="special">)</span><span class="special">;</span></pre>implicit conversion between value types is allowed if allowed for value types themselves </li> 99<li class="listitem"> 100<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> YY<span class="special">></span> 101 <span class="keyword">explicit</span> <a name="id-1_3_44_10_2_36_1_1_3_13-bb"></a><span class="identifier">quantity</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span> source<span class="special">,</span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span> <span class="special">=</span> <span class="number">0</span><span class="special">)</span><span class="special">;</span></pre>implicit conversion between value types is not allowed if not allowed for value types themselves </li> 102<li class="listitem"> 103<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Unit2<span class="special">,</span> <span class="keyword">typename</span> YY<span class="special">></span> 104 <span class="keyword">explicit</span> <a name="id-1_3_44_10_2_36_1_1_3_15-bb"></a><span class="identifier">quantity</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit2</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span> source<span class="special">,</span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span> <span class="special">=</span> <span class="number">0</span><span class="special">)</span><span class="special">;</span></pre>explicit conversion between different unit systems is allowed if implicit conversion is disallowed </li> 105<li class="listitem"> 106<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Unit2<span class="special">,</span> <span class="keyword">typename</span> YY<span class="special">></span> 107 <a name="id-1_3_44_10_2_36_1_1_3_16-bb"></a><span class="identifier">quantity</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit2</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span> source<span class="special">,</span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span> <span class="special">=</span> <span class="number">0</span><span class="special">)</span><span class="special">;</span></pre>implicit conversion between different unit systems is allowed if each fundamental dimension is implicitly convertible </li> 108<li class="listitem"><pre class="literallayout"><span class="keyword">explicit</span> <a name="id-1_3_44_10_2_36_1_1_3_20-bb"></a><span class="identifier">quantity</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">value_type</span> <span class="special">&</span> val<span class="special">,</span> <span class="keyword">int</span><span class="special">)</span><span class="special">;</span></pre></li> 109<li class="listitem"><pre class="literallayout"><span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> <a name="id-1_3_44_10_2_36_1_1_3_11-bb"></a><span class="keyword">operator</span><span class="special">=</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">this_type</span> <span class="special">&</span> source<span class="special">)</span><span class="special">;</span></pre></li> 110<li class="listitem"> 111<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> YY<span class="special">></span> 112 <span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> 113 <a name="id-1_3_44_10_2_36_1_1_3_14-bb"></a><span class="keyword">operator</span><span class="special">=</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span> source<span class="special">)</span><span class="special">;</span></pre>implicit assignment between value types is allowed if allowed for value types themselves </li> 114<li class="listitem"> 115<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Unit2<span class="special">,</span> <span class="keyword">typename</span> YY<span class="special">></span> 116 <span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> 117 <a name="id-1_3_44_10_2_36_1_1_3_17-bb"></a><span class="keyword">operator</span><span class="special">=</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit2</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span> source<span class="special">)</span><span class="special">;</span></pre>implicit assignment between different unit systems is allowed if each fundamental dimension is implicitly convertible </li> 118</ol></div> 119</div> 120<div class="refsect2"> 121<a name="id-1.3.44.10.2.36.5.4.3"></a><h3> 122<a name="id-1_3_44_10_2_36_1_1_3_6-bb"></a><code class="computeroutput">quantity</code> private member functions</h3> 123<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><pre class="literallayout"> <a name="id-1_3_44_10_2_36_1_1_3_6_1-bb"></a><span class="identifier">BOOST_MPL_ASSERT_NOT</span><span class="special">(</span><span class="emphasis"><em><span class="identifier">unspecified</span></em></span><span class="special">)</span><span class="special">;</span></pre></li></ol></div> 124</div> 125<div class="refsect2"> 126<a name="id-1.3.44.10.2.36.5.4.4"></a><h3> 127<a name="id-1_3_44_10_2_36_1_1_3_7-bb"></a><code class="computeroutput">quantity</code> public member functions</h3> 128<div class="orderedlist"><ol class="orderedlist" type="1"> 129<li class="listitem"> 130<pre class="literallayout"><span class="identifier">BOOST_CONSTEXPR</span> <span class="keyword">const</span> <span class="identifier">value_type</span> <span class="special">&</span> <a name="id-1_3_44_10_2_36_1_1_3_7_1-bb"></a><span class="identifier">value</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>constant accessor to value <p>can add a quantity of the same type if add_typeof_helper<value_type,value_type>::type is convertible to value_type </p> 131</li> 132<li class="listitem"> 133<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Unit2<span class="special">,</span> <span class="keyword">typename</span> YY<span class="special">></span> 134 <span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> 135 <a name="id-1_3_44_10_2_36_1_1_3_7_2-bb"></a><span class="keyword">operator</span><span class="special">+=</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit2</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span> source<span class="special">)</span><span class="special">;</span></pre>can subtract a quantity of the same type if subtract_typeof_helper<value_type,value_type>::type is convertible to value_type </li> 136<li class="listitem"><pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Unit2<span class="special">,</span> <span class="keyword">typename</span> YY<span class="special">></span> 137 <span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> 138 <a name="id-1_3_44_10_2_36_1_1_3_7_3-bb"></a><span class="keyword">operator</span><span class="special">-=</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit2</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span> source<span class="special">)</span><span class="special">;</span></pre></li> 139<li class="listitem"><pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Unit2<span class="special">,</span> <span class="keyword">typename</span> YY<span class="special">></span> 140 <span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> 141 <a name="id-1_3_44_10_2_36_1_1_3_7_4-bb"></a><span class="keyword">operator</span> <span class="special">*=</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit2</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span> source<span class="special">)</span><span class="special">;</span></pre></li> 142<li class="listitem"> 143<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Unit2<span class="special">,</span> <span class="keyword">typename</span> YY<span class="special">></span> 144 <span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> 145 <a name="id-1_3_44_10_2_36_1_1_3_7_5-bb"></a><span class="keyword">operator</span><span class="special">/=</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="quantity.html" title="Class template quantity">quantity</a><span class="special"><</span> <span class="identifier">Unit2</span><span class="special">,</span> <span class="identifier">YY</span> <span class="special">></span> <span class="special">&</span> source<span class="special">)</span><span class="special">;</span></pre>can multiply a quantity by a scalar value_type if multiply_typeof_helper<value_type,value_type>::type is convertible to value_type </li> 146<li class="listitem"> 147<pre class="literallayout"><span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> <a name="id-1_3_44_10_2_36_1_1_3_7_6-bb"></a><span class="keyword">operator</span> <span class="special">*=</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">value_type</span> <span class="special">&</span> source<span class="special">)</span><span class="special">;</span></pre>can divide a quantity by a scalar value_type if divide_typeof_helper<value_type,value_type>::type is convertible to value_type </li> 148<li class="listitem"><pre class="literallayout"><span class="identifier">BOOST_CXX14_CONSTEXPR</span> <span class="identifier">this_type</span> <span class="special">&</span> <a name="id-1_3_44_10_2_36_1_1_3_7_7-bb"></a><span class="keyword">operator</span><span class="special">/=</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">value_type</span> <span class="special">&</span> source<span class="special">)</span><span class="special">;</span></pre></li> 149</ol></div> 150</div> 151<div class="refsect2"> 152<a name="id-1.3.44.10.2.36.5.4.5"></a><h3> 153<a name="id-1_3_44_10_2_36_1_1_3_18-bb"></a><code class="computeroutput">quantity</code> public static functions</h3> 154<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> 155<pre class="literallayout"><span class="keyword">static</span> <span class="identifier">BOOST_CONSTEXPR</span> <span class="identifier">this_type</span> <a name="id-1_3_44_10_2_36_1_1_3_18_1-bb"></a><span class="identifier">from_value</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">value_type</span> <span class="special">&</span> val<span class="special">)</span><span class="special">;</span></pre>Construct quantity directly from <code class="computeroutput">value_type</code> (potentially dangerous). </li></ol></div> 156</div> 157<div class="refsect2"> 158<a name="id-1.3.44.10.2.36.5.4.6"></a><h3>Specializations</h3> 159<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p><a class="link" href="quant_1_3_44_10_2_36_1_1_4.html" title="Class template quantity<BOOST_UNITS_DIMENSIONLESS_UNIT(System), Y>">Class template quantity<BOOST_UNITS_DIMENSIONLESS_UNIT(System), Y></a></p></li></ul></div> 160</div> 161</div> 162</div> 163<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 164<td align="left"></td> 165<td align="right"><div class="copyright-footer">Copyright © 2003-2008 Matthias Christian Schabel<br>Copyright © 2007-2010 Steven 166 Watanabe<p> 167 Distributed under the Boost Software License, Version 1.0. (See accompanying 168 file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) 169 </p> 170</div></td> 171</tr></table> 172<hr> 173<div class="spirit-nav"> 174<a accesskey="p" href="add_t_1_3_44_10_2_36_1_1_2.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../boost_units/Reference.html#header.boost.units.quantity_hpp"><img src="../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="quant_1_3_44_10_2_36_1_1_4.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 175</div> 176</body> 177</html> 178