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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::underflow_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
*/
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