1 // Copyright John Maddock 2007.
2 // Copyright Paul A. Bristow 2010
3 // Use, modification and distribution are subject to the
4 // Boost Software License, Version 1.0. (See accompanying file
5 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6
7 #include <iostream>
8 using std::cout; using std::endl;
9 #include <cerrno> // for ::errno
10
11 //[policy_eg_2
12
13 #include <boost/math/special_functions/gamma.hpp>
14 using boost::math::tgamma;
15
main()16 int main()
17 {
18 // using namespace boost::math::policies; // or
19 using boost::math::policies::errno_on_error;
20 using boost::math::policies::make_policy;
21 using boost::math::policies::pole_error;
22 using boost::math::policies::domain_error;
23 using boost::math::policies::overflow_error;
24 using boost::math::policies::evaluation_error;
25
26 errno = 0;
27 std::cout << "Result of tgamma(30000) is: "
28 << boost::math::tgamma(
29 30000,
30 make_policy(
31 domain_error<errno_on_error>(),
32 pole_error<errno_on_error>(),
33 overflow_error<errno_on_error>(),
34 evaluation_error<errno_on_error>()
35 )
36 ) << std::endl;
37 // Check errno was set:
38 std::cout << "errno = " << errno << std::endl;
39 // and again with evaluation at a pole:
40 std::cout << "Result of tgamma(-10) is: "
41 << boost::math::tgamma(
42 -10,
43 make_policy(
44 domain_error<errno_on_error>(),
45 pole_error<errno_on_error>(),
46 overflow_error<errno_on_error>(),
47 evaluation_error<errno_on_error>()
48 )
49 ) << std::endl;
50 // Check errno was set:
51 std::cout << "errno = " << errno << std::endl;
52 }
53
54 //] //[/policy_eg_2]
55
56 /*
57
58 Output:
59
60 Result of tgamma(30000) is: 1.#INF
61 errno = 34
62 Result of tgamma(-10) is: 1.#QNAN
63 errno = 33
64 */
65
66