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POFunction pointers working as closures in C++
 

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    <p>Is there a way in C++ to effectively create a closure which will be a function pointer? I am using the Gnu Scientific Library and I have to create a <a href="http://www.network-theory.co.uk/docs/gslref/Providingthefunctiontosolve.html" rel="nofollow noreferrer">gsl_function</a>. This function needs to effectively "close" a couple of parameters available when I create it. Is there a nice trick to create a closure so that I don't have to pass all of them as params in the gsl_function structure? If not, should I just pass in a pointer to an array containing these parameters?</p> <p><strong>EDIT</strong> I have tried to use boost::bind like this:</p> <pre><code>#include &lt;gsl/gsl_integration.h&gt; #include &lt;boost/bind.hpp&gt; #include "bondpricecalculator.h" #include "functions.h" double integrand (double xi, double t, double x, void * p) { Functions *functions = (Functions *) p; double vx = functions-&gt;v(x); return functions-&gt;rho0(x)*exp(vx * xi - 0.5 * vx * vx * t); } double BondPriceCalculator::value(double t, double T, double xi) { gsl_integration_workspace * w = gsl_integration_workspace_alloc (10000); gsl_function F; F.function = &amp;boost::bind(integrand, xi, t, _1, _2); F.params = &amp;functions; double integral_t; double integral_T; double error; int res = gsl_integration_qags(&amp;F, T, 1e+14, 0, 1e-7, 10000, w, &amp;integral_T, &amp;error); if(res) { throw "Error intgrating"; } int res = gsl_integration_qags(&amp;F, T, 1e+14, 0, 1e-7, 10000, w, &amp;integral_t, &amp;error); if(res) { throw "Error intgrating"; } return integral_T/integral_t; } </code></pre> <p>but I got the following error message:</p> <pre><code>/home/ga/svn/PhD/inflation/cpp/ioi/bondpricecalculator.cpp:20: error: cannot convert ‘boost::_bi::bind_t&lt;double, double (*)(double, double, double, void*), boost::_bi::list4&lt;boost::_bi::value&lt;double&gt;, boost::_bi::value&lt;double&gt;, boost::arg&lt;1&gt;, boost::arg&lt;2&gt; &gt; &gt;*’ to ‘double (*)(double, void*)’ in assignment </code></pre>
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