mp-units/HEAD/api_reference/gen/qty.ref.obs.html

<!DOCTYPE html><html lang='en'><head><title>[qty.ref.obs]</title><meta charset='UTF-8'/><link rel='stylesheet' type='text/css' href='14882.css'/><link rel='stylesheet' type='text/css' href='https://fonts.googleapis.com/css2?family=Noto+Serif'/><link rel='stylesheet' type='text/css' href='https://fonts.googleapis.com/css2?family=Noto+Sans'/><link rel='stylesheet' type='text/css' href='https://fonts.googleapis.com/css2?family=Noto+Sans+Mono'/><link rel='icon' href='icon.png'/><link rel='stylesheet' type='text/css' href='expanded.css' title='Normal'/><link rel='alternate stylesheet' type='text/css' href='colored.css' title='Notes and examples colored'/><link rel='alternate stylesheet' type='text/css' href='normative-only.css' title='Notes and examples hidden'/></head><body><div class='wrapper'><h1 ><a class='secnum' style='min-width:50pt'>5</a> Quantities and units library <a class='abbr_ref' href='index.html#quantities'>[quantities]</a></h1><h2 ><a class='secnum' style='min-width:65pt'>5.4</a> Reference <a class='abbr_ref' href='qty.ref.html#obs'>[qty.ref]</a></h2><h3 ><a class='secnum' style='min-width:80pt'>5.4.9</a> Observers <a class='abbr_ref'>[qty.ref.obs]</a></h3><div class='texpara'><div id='lib:reference,get_quantity_spec'><div id='lib:get_quantity_spec,reference'><div class='itemdecl'><div class='marginalizedparent'><a class='itemDeclLink' href='#lib:get_quantity_spec,reference'>🔗</a></div><code class='itemdeclcode'><span class='keyword'>template</span><span class='anglebracket'>&lt;</span><span class='keyword'>typename</span> Q, <span class='keyword'>typename</span> U<span class='anglebracket'>&gt;</span>
<span class='keyword'>consteval</span> <a href='qty.spec.concepts.html#concept:QuantitySpec' title='5.4.3.2&emsp;Concepts&emsp;[qty.spec.concepts]'><span id='conceptref:QuantitySpec'><span class='texttt'>QuantitySpec</span></span></a> <span class='keyword'>auto</span> get_quantity_spec<span class='parenthesis'>(</span>reference<span class='anglebracket'>&lt;</span>Q, U<span class='anglebracket'>&gt;</span><span class='parenthesis'>)</span>;
</code></div></div></div></div><div class='para' id='1'><div class='marginalizedparent'><a class='marginalized' href='#1'>1</a></div><div class='itemdescr'><div class='sourceLinkParent'><a class='sourceLink' href='https://github.com/mpusz/mp-unitse9c5f7236ebfe1b287a5a4a49aaf57fbefa87233/source/quantities.tex#L3608'>#</a></div><div class='texpara'><div id='1.sentence-1' class='sentence'><i >Returns</i>: <span class='texttt'>Q<span class='curlybracket'>{</span><span class='curlybracket'>}</span></span><a class='hidden_link' href='#1.sentence-1'>.</a></div></div></div></div><div class='texpara'><div id='lib:reference,get_unit'><div id='lib:get_unit,reference'><div class='itemdecl'><div class='marginalizedparent'><a class='itemDeclLink' href='#lib:get_unit,reference'>🔗</a></div><code class='itemdeclcode'><span class='keyword'>template</span><span class='anglebracket'>&lt;</span><span class='keyword'>typename</span> Q, <span class='keyword'>typename</span> U<span class='anglebracket'>&gt;</span>
<span class='keyword'>consteval</span> <a href='qty.unit.concepts.html#concept:Unit' title='5.4.4.4&emsp;Concepts&emsp;[qty.unit.concepts]'><span id='conceptref:Unit'><span class='texttt'>Unit</span></span></a> <span class='keyword'>auto</span> get_unit<span class='parenthesis'>(</span>reference<span class='anglebracket'>&lt;</span>Q, U<span class='anglebracket'>&gt;</span><span class='parenthesis'>)</span>;
</code></div></div></div></div><div class='para' id='2'><div class='marginalizedparent'><a class='marginalized' href='#2'>2</a></div><div class='itemdescr'><div class='sourceLinkParent'><a class='sourceLink' href='https://github.com/mpusz/mp-unitse9c5f7236ebfe1b287a5a4a49aaf57fbefa87233/source/quantities.tex#L3620'>#</a></div><div class='texpara'><div id='2.sentence-1' class='sentence'><i >Returns</i>: <span class='texttt'>U<span class='curlybracket'>{</span><span class='curlybracket'>}</span></span><a class='hidden_link' href='#2.sentence-1'>.</a></div></div></div></div><div class='texpara'><div id='lib:AssociatedUnit,get_common_reference'><div id='lib:get_common_reference,AssociatedUnit'><div class='itemdecl'><div class='marginalizedparent'><a class='itemDeclLink' href='#lib:get_common_reference,AssociatedUnit'>🔗</a></div><code class='itemdeclcode'><span class='keyword'>consteval</span> <a href='qty.unit.concepts.html#concept:AssociatedUnit' title='5.4.4.4&emsp;Concepts&emsp;[qty.unit.concepts]'><span id='conceptref:AssociatedUnit'><span class='texttt'>AssociatedUnit</span></span></a> <span class='keyword'>auto</span> <span id='lib:get_common_reference'><a class='hidden_link' href='#lib:get_common_reference' title='5.4.9&emsp;Observers&emsp;[qty.ref.obs]'>get_common_reference</a></span><span class='parenthesis'>(</span><a href='qty.unit.concepts.html#concept:AssociatedUnit' title='5.4.4.4&emsp;Concepts&emsp;[qty.unit.concepts]'><span id='conceptref:AssociatedUnit_'><span class='texttt'>AssociatedUnit</span></span></a> <span class='keyword'>auto</span> u1,
                                                   <a href='qty.unit.concepts.html#concept:AssociatedUnit' title='5.4.4.4&emsp;Concepts&emsp;[qty.unit.concepts]'><span id='conceptref:AssociatedUnit__'><span class='texttt'>AssociatedUnit</span></span></a> <span class='keyword'>auto</span> u2,
                                                   <a href='qty.unit.concepts.html#concept:AssociatedUnit' title='5.4.4.4&emsp;Concepts&emsp;[qty.unit.concepts]'><span id='conceptref:AssociatedUnit___'><span class='texttt'>AssociatedUnit</span></span></a> <span class='keyword'>auto</span><span class='operator'>.</span><span class='operator'>.</span><span class='operator'>.</span> rest<span class='parenthesis'>)</span>
  <span class='keyword'>requires</span> <i ><span class='texttt'>see below</span></i>;
</code></div></div></div></div><div class='para' id='3'><div class='marginalizedparent'><a class='marginalized' href='#3'>3</a></div><div class='itemdescr'><div class='sourceLinkParent'><a class='sourceLink' href='https://github.com/mpusz/mp-unitse9c5f7236ebfe1b287a5a4a49aaf57fbefa87233/source/quantities.tex#L3634'>#</a></div><div class='texpara'><div id='3.sentence-1' class='sentence'><i >Returns</i>: <span class='texttt'>get_<span class='shy'></span>common_<span class='shy'></span>unit<span class='parenthesis'>(</span>u1, u2, rest<span class='operator'>.</span><span class='operator'>.</span><span class='operator'>.</span><span class='parenthesis'>)</span></span><a class='hidden_link' href='#3.sentence-1'>.</a></div></div></div></div><div class='para' id='4'><div class='marginalizedparent'><a class='marginalized' href='#4'>4</a></div><div class='itemdescr'><div class='sourceLinkParent'><a class='sourceLink' href='https://github.com/mpusz/mp-unitse9c5f7236ebfe1b287a5a4a49aaf57fbefa87233/source/quantities.tex#L3638'>#</a></div><div class='texpara'><div id='4.sentence-1' class='sentence'><i >Remarks</i>: The expression in the <span class='textsf'><i >requires-clause</i></span> is equivalent to:
<span class='codeblock'><span class='keyword'>requires</span> <span class='curlybracket'>{</span>
  get_common_quantity_spec<span class='parenthesis'>(</span>get_quantity_spec<span class='parenthesis'>(</span>u1<span class='parenthesis'>)</span>, get_quantity_spec<span class='parenthesis'>(</span>u2<span class='parenthesis'>)</span>,
                           get_quantity_spec<span class='parenthesis'>(</span>rest<span class='parenthesis'>)</span><span class='operator'>.</span><span class='operator'>.</span><span class='operator'>.</span><span class='parenthesis'>)</span>;
  <span class='curlybracket'>{</span> get_common_unit<span class='parenthesis'>(</span>u1, u2, rest<span class='operator'>.</span><span class='operator'>.</span><span class='operator'>.</span><span class='parenthesis'>)</span> <span class='curlybracket'>}</span> <span class='operator'>-</span><span class='anglebracket'>&gt;</span> AssociatedUnit;
<span class='curlybracket'>}</span>
</span></div></div></div></div><div class='texpara'><div id='lib:reference,get_common_reference'><div id='lib:get_common_reference,reference'><div class='itemdecl'><div class='marginalizedparent'><a class='itemDeclLink' href='#lib:get_common_reference,reference'>🔗</a></div><code class='itemdeclcode'><span class='keyword'>template</span><span class='anglebracket'>&lt;</span><a href='qty.ref.concepts.html#concept:Reference' title='5.4.5&emsp;Concepts&emsp;[qty.ref.concepts]'><span id='conceptref:Reference'><span class='texttt'>Reference</span></span></a> R1, <a href='qty.ref.concepts.html#concept:Reference' title='5.4.5&emsp;Concepts&emsp;[qty.ref.concepts]'><span id='conceptref:Reference_'><span class='texttt'>Reference</span></span></a> R2, <a href='qty.ref.concepts.html#concept:Reference' title='5.4.5&emsp;Concepts&emsp;[qty.ref.concepts]'><span id='conceptref:Reference__'><span class='texttt'>Reference</span></span></a><span class='operator'>.</span><span class='operator'>.</span><span class='operator'>.</span> Rest<span class='anglebracket'>&gt;</span>
<span class='keyword'>consteval</span> <a href='qty.ref.concepts.html#concept:Reference' title='5.4.5&emsp;Concepts&emsp;[qty.ref.concepts]'><span id='conceptref:Reference___'><span class='texttt'>Reference</span></span></a> <span class='keyword'>auto</span> <span id='lib:get_common_reference_'><a class='hidden_link' href='#lib:get_common_reference' title='5.4.9&emsp;Observers&emsp;[qty.ref.obs]'>get_common_reference</a></span><span class='parenthesis'>(</span>R1 r1, R2 r2, Rest<span class='operator'>.</span><span class='operator'>.</span><span class='operator'>.</span> rest<span class='parenthesis'>)</span>
  <span class='keyword'>requires</span> <i ><span class='texttt'>see below</span></i>;
</code></div></div></div></div><div class='para' id='5'><div class='marginalizedparent'><a class='marginalized' href='#5'>5</a></div><div class='itemdescr'><div class='sourceLinkParent'><a class='sourceLink' href='https://github.com/mpusz/mp-unitse9c5f7236ebfe1b287a5a4a49aaf57fbefa87233/source/quantities.tex#L3658'>#</a></div><div class='texpara'><div id='5.sentence-1' class='sentence'><i >Returns</i>: <span class='codeblock'><i >reference-t</i><span class='anglebracket'>&lt;</span>get_common_quantity_spec<span class='parenthesis'>(</span>get_quantity_spec<span class='parenthesis'>(</span>R1<span class='curlybracket'>{</span><span class='curlybracket'>}</span><span class='parenthesis'>)</span>, get_quantity_spec<span class='parenthesis'>(</span>R2<span class='curlybracket'>{</span><span class='curlybracket'>}</span><span class='parenthesis'>)</span>,
                                     get_quantity_spec<span class='parenthesis'>(</span>rest<span class='parenthesis'>)</span><span class='operator'>.</span><span class='operator'>.</span><span class='operator'>.</span><span class='parenthesis'>)</span>,
            get_common_unit<span class='parenthesis'>(</span>get_unit<span class='parenthesis'>(</span>R1<span class='curlybracket'>{</span><span class='curlybracket'>}</span><span class='parenthesis'>)</span>, get_unit<span class='parenthesis'>(</span>R2<span class='curlybracket'>{</span><span class='curlybracket'>}</span><span class='parenthesis'>)</span>, get_unit<span class='parenthesis'>(</span>rest<span class='parenthesis'>)</span><span class='operator'>.</span><span class='operator'>.</span><span class='operator'>.</span><span class='parenthesis'>)</span><span class='anglebracket'>&gt;</span><span class='curlybracket'>{</span><span class='curlybracket'>}</span>;
</span></div></div></div></div><div class='para' id='6'><div class='marginalizedparent'><a class='marginalized' href='#6'>6</a></div><div class='itemdescr'><div class='sourceLinkParent'><a class='sourceLink' href='https://github.com/mpusz/mp-unitse9c5f7236ebfe1b287a5a4a49aaf57fbefa87233/source/quantities.tex#L3666'>#</a></div><div class='texpara'><div id='6.sentence-1' class='sentence'><i >Remarks</i>: The expression in the <span class='textsf'><i >requires-clause</i></span> is equivalent to:
<span class='codeblock'><span class='keyword'>requires</span> <span class='curlybracket'>{</span>
  get_common_quantity_spec<span class='parenthesis'>(</span>get_quantity_spec<span class='parenthesis'>(</span>r1<span class='parenthesis'>)</span>, get_quantity_spec<span class='parenthesis'>(</span>r2<span class='parenthesis'>)</span>,
                           get_quantity_spec<span class='parenthesis'>(</span>rest<span class='parenthesis'>)</span><span class='operator'>.</span><span class='operator'>.</span><span class='operator'>.</span><span class='parenthesis'>)</span>;
  get_common_unit<span class='parenthesis'>(</span>get_unit<span class='parenthesis'>(</span>r1<span class='parenthesis'>)</span>, get_unit<span class='parenthesis'>(</span>r2<span class='parenthesis'>)</span>, get_unit<span class='parenthesis'>(</span>rest<span class='parenthesis'>)</span><span class='operator'>.</span><span class='operator'>.</span><span class='operator'>.</span><span class='parenthesis'>)</span>;
<span class='curlybracket'>}</span>
</span></div></div></div></div></div></body></html>