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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
- */
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