Initial commit

libs/math/example/policy_eg_1.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_1
+
+#include <boost/math/special_functions/gamma.hpp>
+using boost::math::tgamma;
+
+// Define the policy to use:
+using namespace boost::math::policies; // may be convenient, or
+
+using boost::math::policies::policy;
+// Types of error whose action can be altered by policies:.
+using boost::math::policies::evaluation_error;
+using boost::math::policies::domain_error;
+using boost::math::policies::overflow_error;
+using boost::math::policies::domain_error;
+using boost::math::policies::pole_error;
+// Actions on error (in enum error_policy_type):
+using boost::math::policies::errno_on_error;
+using boost::math::policies::ignore_error;
+using boost::math::policies::throw_on_error;
+using boost::math::policies::user_error;
+
+typedef policy<
+   domain_error<errno_on_error>,
+   pole_error<errno_on_error>,
+   overflow_error<errno_on_error>,
+   evaluation_error<errno_on_error> 
+> c_policy;
+//
+// Now use the policy when calling tgamma:
+
+// http://msdn.microsoft.com/en-us/library/t3ayayh1.aspx 
+// Microsoft errno declared in STDLIB.H as "extern int errno;" 
+
+int main()
+{
+   errno = 0; // Reset.
+   cout << "Result of tgamma(30000) is: " 
+      << tgamma(30000, c_policy()) << endl; // Too big parameter
+   cout << "errno = " << errno << endl; // errno 34 Numerical result out of range.
+   cout << "Result of tgamma(-10) is: " 
+      << boost::math::tgamma(-10, c_policy()) << endl; // Negative parameter.
+   cout << "errno = " << errno << endl; // error 33 Numerical argument out of domain.
+} // int main()
+
+//]
+
+/* Output
+
+policy_eg_1.cpp
+  Generating code
+  Finished generating code
+  policy_eg_1.vcxproj -> J:\Cpp\MathToolkit\test\Math_test\Release\policy_eg_1.exe
+  Result of tgamma(30000) is: 1.#INF
+  errno = 34
+  Result of tgamma(-10) is: 1.#QNAN
+  errno = 33
+
+*/
+
+