| // 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) |
| |
| // Note that this file contains quickbook mark-up as well as code |
| // and comments, don't change any of the special comment mark-ups! |
| |
| #include <iostream> |
| using std::cout; using std::endl; |
| #include <cerrno> // for ::errno |
| |
| //[policy_eg_5 |
| |
| #include <boost/math/special_functions.hpp> |
| // using boost::math::tgamma; // Would create an ambiguity between |
| // 'double boost::math::tgamma<int>(T)' and |
| // 'double 'anonymous-namespace'::tgamma<int>(RT)'. |
| |
| namespace |
| { // unnamed |
| |
| using namespace boost::math::policies; |
| |
| typedef policy< |
| domain_error<errno_on_error>, |
| pole_error<errno_on_error>, |
| overflow_error<errno_on_error>, |
| evaluation_error<errno_on_error> |
| > c_policy; |
| |
| BOOST_MATH_DECLARE_SPECIAL_FUNCTIONS(c_policy) |
| |
| /*` |
| So that when we call `tgamma(z)`, we really end up calling |
| `boost::math::tgamma(z, anonymous-namespace::c_policy())`. |
| */ |
| |
| } // close unnamed namespace |
| |
| int main() |
| { |
| errno = 0; |
| cout << "Result of tgamma(30000) is: " |
| << tgamma(30000) << endl; |
| // tgamma in unnamed namespace in this translation unit (file) only. |
| cout << "errno = " << errno << endl; |
| cout << "Result of tgamma(-10) is: " |
| << tgamma(-10) << endl; |
| cout << "errno = " << errno << endl; |
| // Default tgamma policy would throw an exception, and abort. |
| } |
| |
| //] //[/policy_eg_5] |
| |
| /* |
| Output: |
| |
| Result of tgamma(30000) is: 1.#INF |
| errno = 34 |
| Result of tgamma(-10) is: 1.#QNAN |
| errno = 33 |
| |
| |
| */ |