1 2 // Copyright (C) 2008-2018 Lorenzo Caminiti 3 // Distributed under the Boost Software License, Version 1.0 (see accompanying 4 // file LICENSE_1_0.txt or a copy at http://www.boost.org/LICENSE_1_0.txt). 5 // See: http://www.boost.org/doc/libs/release/libs/contract/doc/html/index.html 6 7 #include <limits> 8 #include <cassert> 9 10 //[non_member 11 #include <boost/contract.hpp> 12 13 // Contract for a non-member function. inc(int & x)14int inc(int& x) { 15 int result; 16 boost::contract::old_ptr<int> old_x = BOOST_CONTRACT_OLDOF(x); 17 boost::contract::check c = boost::contract::function() 18 .precondition([&] { 19 BOOST_CONTRACT_ASSERT(x < std::numeric_limits<int>::max()); 20 }) 21 .postcondition([&] { 22 BOOST_CONTRACT_ASSERT(x == *old_x + 1); 23 BOOST_CONTRACT_ASSERT(result == *old_x); 24 }) 25 .except([&] { 26 BOOST_CONTRACT_ASSERT(x == *old_x); 27 }) 28 ; 29 30 return result = x++; // Function body. 31 } 32 //] 33 main()34int main() { 35 int x = std::numeric_limits<int>::max() - 1; 36 assert(inc(x) == std::numeric_limits<int>::max() - 1); 37 assert(x == std::numeric_limits<int>::max()); 38 return 0; 39 } 40 41