libs/contract/example/features/non_member.cpp
// Copyright (C) 2008-2018 Lorenzo Caminiti
// Distributed under the Boost Software License, Version 1.0 (see accompanying
// file LICENSE_1_0.txt or a copy at http://www.boost.org/LICENSE_1_0.txt).
// See: http://www.boost.org/doc/libs/release/libs/contract/doc/html/index.html
#include <limits>
#include <cassert>
//[non_member
#include <boost/contract.hpp>
// Contract for a non-member function.
int inc(int& x) {
int result;
boost::contract::old_ptr<int> old_x = BOOST_CONTRACT_OLDOF(x);
boost::contract::check c = boost::contract::function()
.precondition([&] {
BOOST_CONTRACT_ASSERT(x < std::numeric_limits<int>::max());
})
.postcondition([&] {
BOOST_CONTRACT_ASSERT(x == *old_x + 1);
BOOST_CONTRACT_ASSERT(result == *old_x);
})
.except([&] {
BOOST_CONTRACT_ASSERT(x == *old_x);
})
;
return result = x++; // Function body.
}
//]
int main() {
int x = std::numeric_limits<int>::max() - 1;
assert(inc(x) == std::numeric_limits<int>::max() - 1);
assert(x == std::numeric_limits<int>::max());
return 0;
}