call function when leaving scope
c++, c++11, raii, scope
Solution
Using a constructor/destructor in this way is a common way to solve this sort problem. I have used it for both locks (constructor takes lock, destructor releases it) and logging purposes (constructor prints something on construction, and destructor prints on destruction, giving a nice callgraph of a project - in the latter case, using macros to also get `__FILE__` and `__LINE__` store in the object, so we can see where the constructor was called [it's almost impossible to do this for the destructor, but typically it's possible to see the constructor and make out where the destructor gets called]).
Problem
What is the most elegant solution for calling a function automatically when leaving a scope? My current approach (see below) works but I guess there should be something more general as writing a custom class for this. ``` #include <iostream> #include <functional> using namespace std; class DoInDtor { public: typedef function<void()> F; DoInDtor(F f) : f_(f) {}; ~DoInDtor() { f_(); } private: F f_; }; void foo() { DoInDtor byeSayerCustom([](){ cout << "bye\n"; }); auto cond = true; // could of course also be false if ( cond ) return; return; } int main() { foo(); } ``` Sure, one could abuse std::unique_ptr and its custom deleter, but since I am not really acquiring a resource here, that does not sound great to me either in terms of code readability. Any suggestions?