<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/> <title>libsigc++: compose()</title> <link href="tabs.css" rel="stylesheet" type="text/css"/> <link href="doxygen.css" rel="stylesheet" type="text/css"/> </head> <body> <!-- Generated by Doxygen 1.7.2 --> <div class="navigation" id="top"> <div class="tabs"> <ul class="tablist"> <li><a href="index.html"><span>Main Page</span></a></li> <li><a href="modules.html"><span>Modules</span></a></li> <li><a href="namespaces.html"><span>Namespaces</span></a></li> <li><a href="annotated.html"><span>Classes</span></a></li> </ul> </div> </div> <div class="header"> <div class="summary"> <a href="#nested-classes">Classes</a> | <a href="#func-members">Functions</a> </div> <div class="headertitle"> <h1>compose()<br/> <small> [<a class="el" href="group__adaptors.html">Adaptors</a>]</small> </h1> </div> </div> <div class="contents"> <p>sigc::compose() combines two or three arbitrary functors. <a href="#_details">More...</a></p> <table class="memberdecls"> <tr><td colspan="2"><h2><a name="nested-classes"></a> Classes</h2></td></tr> <tr><td class="memItemLeft" align="right" valign="top">struct  </td><td class="memItemRight" valign="bottom"><a class="el" href="structsigc_1_1compose1__functor.html">sigc::compose1_functor< T_setter, T_getter ></a></td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Adaptor that combines two functors. <a href="structsigc_1_1compose1__functor.html#_details">More...</a><br/></td></tr> <tr><td class="memItemLeft" align="right" valign="top">struct  </td><td class="memItemRight" valign="bottom"><a class="el" href="structsigc_1_1compose2__functor.html">sigc::compose2_functor< T_setter, T_getter1, T_getter2 ></a></td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Adaptor that combines three functors. <a href="structsigc_1_1compose2__functor.html#_details">More...</a><br/></td></tr> <tr><td colspan="2"><h2><a name="func-members"></a> Functions</h2></td></tr> <tr><td class="memTemplParams" colspan="2">template<class T_action , class T_setter , class T_getter > </td></tr> <tr><td class="memTemplItemLeft" align="right" valign="top">void </td><td class="memTemplItemRight" valign="bottom"><a class="el" href="group__compose.html#ga3e7453863caa786e5e6a0401a8450958">sigc::visit_each</a> (const T_action& _A_action, const compose1_functor< T_setter, T_getter >& _A_target)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Performs a functor on each of the targets of a functor. <a href="#ga3e7453863caa786e5e6a0401a8450958"></a><br/></td></tr> <tr><td class="memTemplParams" colspan="2">template<class T_action , class T_setter , class T_getter1 , class T_getter2 > </td></tr> <tr><td class="memTemplItemLeft" align="right" valign="top">void </td><td class="memTemplItemRight" valign="bottom"><a class="el" href="group__compose.html#ga234770a49ae510afbf6530047005294e">sigc::visit_each</a> (const T_action& _A_action, const compose2_functor< T_setter, T_getter1, T_getter2 >& _A_target)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Performs a functor on each of the targets of a functor. <a href="#ga234770a49ae510afbf6530047005294e"></a><br/></td></tr> <tr><td class="memTemplParams" colspan="2">template<class T_setter , class T_getter > </td></tr> <tr><td class="memTemplItemLeft" align="right" valign="top">compose1_functor< T_setter, <br class="typebreak"/> T_getter > </td><td class="memTemplItemRight" valign="bottom"><a class="el" href="group__compose.html#ga57692495ec80dd855d4653adde4c8f49">sigc::compose</a> (const T_setter& _A_setter, const T_getter& _A_getter)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Creates an adaptor of type <a class="el" href="structsigc_1_1compose1__functor.html" title="Adaptor that combines two functors.">sigc::compose1_functor</a> which combines two functors. <a href="#ga57692495ec80dd855d4653adde4c8f49"></a><br/></td></tr> <tr><td class="memTemplParams" colspan="2">template<class T_setter , class T_getter1 , class T_getter2 > </td></tr> <tr><td class="memTemplItemLeft" align="right" valign="top">compose2_functor< T_setter, <br class="typebreak"/> T_getter1, T_getter2 > </td><td class="memTemplItemRight" valign="bottom"><a class="el" href="group__compose.html#ga5ccef00a13aa5672806c46d4abe4ce55">sigc::compose</a> (const T_setter& _A_setter, const T_getter1& _A_getter1, const T_getter2& _A_getter2)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Creates an adaptor of type <a class="el" href="structsigc_1_1compose2__functor.html" title="Adaptor that combines three functors.">sigc::compose2_functor</a> which combines three functors. <a href="#ga5ccef00a13aa5672806c46d4abe4ce55"></a><br/></td></tr> </table> <hr/><a name="_details"></a><h2>Detailed Description</h2> <p>sigc::compose() combines two or three arbitrary functors. </p> <p>On invokation, parameters are passed on to one or two getter functor(s). The return value(s) are then passed on to the setter function.</p> <dl class="user"><dt><b>Examples:</b></dt><dd><div class="fragment"><pre class="fragment"> <span class="keywordtype">float</span> square_root(<span class="keywordtype">float</span> a) { <span class="keywordflow">return</span> sqrtf(a); } <span class="keywordtype">float</span> <a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01175.html#ga00295ac42c201866e7178edb6878b316">sum</a>(<span class="keywordtype">float</span> a, <span class="keywordtype">float</span> b) { <span class="keywordflow">return</span> a+b; } <a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01134.html#aaf93fdf0812752e0e02c501dea1b38f0">std::cout</a> << <a class="code" href="group__compose.html#ga57692495ec80dd855d4653adde4c8f49" title="Creates an adaptor of type sigc::compose1_functor which combines two functors.">sigc::compose</a>(&square_root, &<a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01175.html#ga00295ac42c201866e7178edb6878b316">sum</a>)(9, 16); <span class="comment">// calls square_root(sum(3,6))</span> <a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01134.html#aaf93fdf0812752e0e02c501dea1b38f0">std::cout</a> << <a class="code" href="group__compose.html#ga57692495ec80dd855d4653adde4c8f49" title="Creates an adaptor of type sigc::compose1_functor which combines two functors.">sigc::compose</a>(&<a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01175.html#ga00295ac42c201866e7178edb6878b316">sum</a>, &square_root, &square_root)(9); <span class="comment">// calls sum(square_root(9), square_root(9))</span> </pre></div></dd></dl> <p>The functor sigc::compose() returns can be passed directly into <a class="el" href="classsigc_1_1signal7.html#adc55ac9b0f935fd87a67904022e03cb2" title="Add a slot to the list of slots.">sigc::signal::connect()</a>.</p> <dl class="user"><dt><b>Example:</b></dt><dd><div class="fragment"><pre class="fragment"> <a class="code" href="classsigc_1_1signal.html" title="Convenience wrapper for the numbered sigc::signal# templates.">sigc::signal<float,float,float></a> some_signal; some_signal.<a class="code" href="classsigc_1_1signal7.html#adc55ac9b0f935fd87a67904022e03cb2" title="Add a slot to the list of slots.">connect</a>(<a class="code" href="group__compose.html#ga57692495ec80dd855d4653adde4c8f49" title="Creates an adaptor of type sigc::compose1_functor which combines two functors.">sigc::compose</a>(&square_root, &<a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01175.html#ga00295ac42c201866e7178edb6878b316">sum</a>)); </pre></div></dd></dl> <p>For a more powerful version of this functionality see the lambda library adaptor sigc::group() which can bind, hide and reorder arguments arbitrarily. Although sigc::group() is more flexible, sigc::bind() provides a means of binding parameters when the total number of parameters called is variable. </p> <hr/><h2>Function Documentation</h2> <a class="anchor" id="ga57692495ec80dd855d4653adde4c8f49"></a><!-- doxytag: member="sigc::compose" ref="ga57692495ec80dd855d4653adde4c8f49" args="(const T_setter &_A_setter, const T_getter &_A_getter)" --> <div class="memitem"> <div class="memproto"> <div class="memtemplate"> template <class T_setter , class T_getter > </div> <table class="memname"> <tr> <td class="memname">compose1_functor<T_setter, T_getter> sigc::compose </td> <td>(</td> <td class="paramtype">const T_setter & </td> <td class="paramname"> <em>_A_setter</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">const T_getter & </td> <td class="paramname"> <em>_A_getter</em> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td><code> [inline]</code></td> </tr> </table> </div> <div class="memdoc"> <p>Creates an adaptor of type <a class="el" href="structsigc_1_1compose1__functor.html" title="Adaptor that combines two functors.">sigc::compose1_functor</a> which combines two functors. </p> <dl><dt><b>Parameters:</b></dt><dd> <table class="params"> <tr><td class="paramname">_A_setter</td><td>Functor that receives the return value of the invokation of <em>_A_getter</em>. </td></tr> <tr><td class="paramname">_A_getter</td><td>Functor to invoke from operator()(). </td></tr> </table> </dd> </dl> <dl class="return"><dt><b>Returns:</b></dt><dd>Adaptor that executes <em>_A_setter</em> with the value returned from invokation of <em>_A_getter</em>. </dd></dl> </div> </div> <a class="anchor" id="ga5ccef00a13aa5672806c46d4abe4ce55"></a><!-- doxytag: member="sigc::compose" ref="ga5ccef00a13aa5672806c46d4abe4ce55" args="(const T_setter &_A_setter, const T_getter1 &_A_getter1, const T_getter2 &_A_getter2)" --> <div class="memitem"> <div class="memproto"> <div class="memtemplate"> template <class T_setter , class T_getter1 , class T_getter2 > </div> <table class="memname"> <tr> <td class="memname">compose2_functor<T_setter, T_getter1, T_getter2> sigc::compose </td> <td>(</td> <td class="paramtype">const T_setter & </td> <td class="paramname"> <em>_A_setter</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">const T_getter1 & </td> <td class="paramname"> <em>_A_getter1</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">const T_getter2 & </td> <td class="paramname"> <em>_A_getter2</em> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td><code> [inline]</code></td> </tr> </table> </div> <div class="memdoc"> <p>Creates an adaptor of type <a class="el" href="structsigc_1_1compose2__functor.html" title="Adaptor that combines three functors.">sigc::compose2_functor</a> which combines three functors. </p> <dl><dt><b>Parameters:</b></dt><dd> <table class="params"> <tr><td class="paramname">_A_setter</td><td>Functor that receives the return values of the invokation of <em>_A_getter1</em> and <em>_A_getter2</em>. </td></tr> <tr><td class="paramname">_A_getter1</td><td>Functor to invoke from operator()(). </td></tr> <tr><td class="paramname">_A_getter2</td><td>Functor to invoke from operator()(). </td></tr> </table> </dd> </dl> <dl class="return"><dt><b>Returns:</b></dt><dd>Adaptor that executes <em>_A_setter</em> with the values return from invokation of <em>_A_getter1</em> and <em>_A_getter2</em>. </dd></dl> </div> </div> <a class="anchor" id="ga3e7453863caa786e5e6a0401a8450958"></a><!-- doxytag: member="sigc::visit_each" ref="ga3e7453863caa786e5e6a0401a8450958" args="(const T_action &_A_action, const compose1_functor< T_setter, T_getter > &_A_target)" --> <div class="memitem"> <div class="memproto"> <div class="memtemplate"> template <class T_action , class T_setter , class T_getter > </div> <table class="memname"> <tr> <td class="memname">void sigc::visit_each </td> <td>(</td> <td class="paramtype">const T_action & </td> <td class="paramname"> <em>_A_action</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">const compose1_functor< T_setter, T_getter > & </td> <td class="paramname"> <em>_A_target</em> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td> </tr> </table> </div> <div class="memdoc"> <p>Performs a functor on each of the targets of a functor. </p> <p>The function overload for <a class="el" href="structsigc_1_1compose1__functor.html" title="Adaptor that combines two functors.">sigc::compose1_functor</a> performs a functor on the functors stored in the <a class="el" href="structsigc_1_1compose1__functor.html" title="Adaptor that combines two functors.">sigc::compose1_functor</a> object. </p> </div> </div> <a class="anchor" id="ga234770a49ae510afbf6530047005294e"></a><!-- doxytag: member="sigc::visit_each" ref="ga234770a49ae510afbf6530047005294e" args="(const T_action &_A_action, const compose2_functor< T_setter, T_getter1, T_getter2 > &_A_target)" --> <div class="memitem"> <div class="memproto"> <div class="memtemplate"> template <class T_action , class T_setter , class T_getter1 , class T_getter2 > </div> <table class="memname"> <tr> <td class="memname">void sigc::visit_each </td> <td>(</td> <td class="paramtype">const T_action & </td> <td class="paramname"> <em>_A_action</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">const compose2_functor< T_setter, T_getter1, T_getter2 > & </td> <td class="paramname"> <em>_A_target</em> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td> </tr> </table> </div> <div class="memdoc"> <p>Performs a functor on each of the targets of a functor. </p> <p>The function overload for <a class="el" href="structsigc_1_1compose2__functor.html" title="Adaptor that combines three functors.">sigc::compose2_functor</a> performs a functor on the functors stored in the <a class="el" href="structsigc_1_1compose2__functor.html" title="Adaptor that combines three functors.">sigc::compose2_functor</a> object. </p> </div> </div> </div> <hr class="footer"/><address class="footer"><small>Generated on Tue Mar 8 2011 11:44:40 for libsigc++ by  <a href="http://www.doxygen.org/index.html"> <img class="footer" src="doxygen.png" alt="doxygen"/></a> 1.7.2 </small></address> </body> </html>