C++ equivalent to Go's defer keyword. Extracted from GSL, see final_action and finally at https://github.com/microsoft/GSL/blob/master/include/gsl/gsl_util

gsl_defer.cpp

#include <iostream>
#include <utility>

// Deferred allows you to ensure something gets run at the end of a scope
template <class F>
class Deferred {
public:
    explicit Deferred(F f) noexcept : fn(std::move(f)) {}
    Deferred(Deferred&& other) noexcept : fn(std::move(other.fn)), called(std::exchange(other.called, false)) {}
    Deferred(const Deferred&) = delete;
    Deferred& operator=(const Deferred&) = delete;
    Deferred& operator=(Deferred&&) = delete;

    ~Deferred() noexcept {
        if (called) fn();
    }

private:
    F fn;
    bool called{true};
};

// defer() - convenience function to generate a Deferred
template <class F>
Deferred<F> defer(const F& f) noexcept {
    return Deferred<F>(f);
}

template <class F>
Deferred<F> defer(F&& f) noexcept {
    return Deferred<F>(std::forward<F>(f));
}

int main() {
  auto _ = defer ([](){
    std::cout << "Hi, I have been deferred :)" << std::endl;
  });
  std::cout << "Hello World!" << std::endl;
}