Initial commit

libs/math/example/policy_eg_2.cpp

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+//  Copyright John Maddock 2007.
+//  Copyright Paul A. Bristow 2010
+//  Use, modification and distribution are subject to the
+//  Boost Software License, Version 1.0. (See accompanying file
+//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#include <iostream>
+using std::cout; using std::endl;
+#include <cerrno> // for ::errno
+
+//[policy_eg_2
+
+#include <boost/math/special_functions/gamma.hpp>
+using boost::math::tgamma;
+
+int main()
+{
+   // using namespace boost::math::policies; // or
+   using boost::math::policies::errno_on_error;
+   using boost::math::policies::make_policy;
+   using boost::math::policies::pole_error;
+   using boost::math::policies::domain_error;
+   using boost::math::policies::overflow_error;
+   using boost::math::policies::evaluation_error;
+
+   errno = 0;
+   std::cout << "Result of tgamma(30000) is: " 
+      << boost::math::tgamma(
+         30000, 
+         make_policy(
+            domain_error<errno_on_error>(),
+            pole_error<errno_on_error>(),
+            overflow_error<errno_on_error>(),
+            evaluation_error<errno_on_error>() 
+         )
+      ) << std::endl;
+   // Check errno was set:
+   std::cout << "errno = " << errno << std::endl;
+   // and again with evaluation at a pole:
+   std::cout << "Result of tgamma(-10) is: " 
+      << boost::math::tgamma(
+         -10, 
+         make_policy(
+            domain_error<errno_on_error>(),
+            pole_error<errno_on_error>(),
+            overflow_error<errno_on_error>(),
+            evaluation_error<errno_on_error>() 
+         )
+      ) << std::endl;
+   // Check errno was set:
+   std::cout << "errno = " << errno << std::endl;
+}
+
+//] //[/policy_eg_2]
+
+/*
+
+Output:
+
+  Result of tgamma(30000) is: 1.#INF
+  errno = 34
+  Result of tgamma(-10) is: 1.#QNAN
+  errno = 33
+*/
+