an example/test uses a dangling reference

[jhcarl0814]

libs/local_function/test/return_assign.cpp uses a dangling reference:

#include <boost/local_function.hpp>
#include <boost/function.hpp>
#include <boost/detail/lightweight_test.hpp>
#include <iostream>

//[return_assign
void call1(boost::function<int (int) > f) { BOOST_TEST(f(1) == 5); }
void call0(boost::function<int (void)> f) { BOOST_TEST(f() == 5); }

boost::function<int (int, int)> linear(const int& slope) {
 int BOOST_LOCAL_FUNCTION(const bind& slope,
 int x, default 1, int y, default 2) {
 return x + slope * y;
 } BOOST_LOCAL_FUNCTION_NAME(lin)

 boost::function<int (int, int)> f = lin; // Assign to local variable.
 BOOST_TEST(f(1, 2) == 5);

 call1(lin); // Pass to other functions.
 call0(lin);

 return lin; // Return.
}

void call(void) {
 boost::function<int (int, int)> f = linear(2); // create temporary, bind reference to temporary
 BOOST_TEST(f(1, 2) == 5); // !!!!!!!!!!!!!!!!!!!!!!!! use the reference
}
//]

int main(void) {
 call();
 return boost::report_errors();
}

changing the target from temporary to local variable can let the test fail:

#include <boost/local_function.hpp>
#include <boost/function.hpp>
#include <boost/detail/lightweight_test.hpp>
#include <iostream>

//[return_assign
void call1(boost::function<int(int) > f) { BOOST_TEST(f(1) == 5); }
void call0(boost::function<int(void)> f) { BOOST_TEST(f() == 5); }

boost::function<int(int, int)> linear(const int& slope) {
 int BOOST_LOCAL_FUNCTION(const bind & slope,
 int x, default 1, int y, default 2) {
 return x + slope * y;
 } BOOST_LOCAL_FUNCTION_NAME(lin)

 boost::function<int(int, int)> f = lin; // Assign to local variable.
 BOOST_TEST(f(1, 2) == 5);

 call1(lin); // Pass to other functions.
 call0(lin);

 return lin; // Return.
}

void call1(void) {
 boost::function<int(int, int)> f = linear(2);
 BOOST_TEST(f(1, 2) == 5); // !!!!!!!!!!!!!!!!!!!!!!!! test passed, although dangling reference
}
void call2(void) {
 int a = 2;
 boost::function<int(int, int)> f = linear(a);
 a = 3;
 BOOST_TEST(f(1, 2) == 5); // !!!!!!!!!!!!!!!!!!!!!!!! test failed
}
//]

int main(void) {
 call1();
 call2();
 return boost::report_errors();
}