// bll_and_function.cpp -------------------------------- // test using BLL and boost::function #define BOOST_INCLUDE_MAIN // for testing, include rather than link #include // see "Header Implementation Option" #include "boost/lambda/lambda.hpp" #include "boost/function.hpp" #include #include #include #include using namespace boost::lambda; using namespace std; void test_function() { boost::function f; f = unlambda(_1 + _2); // unlambda must be used, because boost::function tries to take the // address of the function object that is assigned. However, the // operator& is overloaded for lambda functors, which creates a conflict BOOST_TEST(f(1, 2)== 3); int i=1; int j=2; boost::function g = unlambda(_1 += _2); g(i, j); BOOST_TEST(i==3); int* sum = new int(); *sum = 0; boost::function counter = unlambda(*sum += _1); counter(5); // ok, sum* = 5; BOOST_TEST(*sum == 5); delete sum; // The next statement would lead to a dangling reference // counter(3); // error, *sum does not exist anymore } int test_main(int, char *[]) { test_function(); return 0; }