When I take an object by reference in a C ++ 11 lambda, let the object go out of scope and then execute the lambda, it still has access to the object. When I execute the following code, the lambda call can access the object, although the destructor has already been called! Can someone explain why this works and why I am not getting a runtime error?
#include <iostream>
class MyClass {
public:
int health = 5;
MyClass() {std::cout << "MyClass created!\n";}
~MyClass() {std::cout << "MyClass destroyed!\n";}
};
int main(int argc, const char * argv[])
{
std::function<bool (int)> checkHealth;
if(true) {
MyClass myVanishingObject;
checkHealth = [&myVanishingObject] (int minimumHealth) -> bool {
std::cout << myVanishingObject.health << std::endl;
return myVanishingObject.health >= minimumHealth;
};
}
if(checkHealth(4)) {
std::cout << "has enough health\n";
} else {
std::cout << "doesn't have enough health\n";
}
return 0;
}
Here's the conclusion:
MyClass created!
MyClass destroyed!
5
has enough health
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