Skip to content

Instantly share code, notes, and snippets.

What would you like to do?
A single function that uses a bunch of C++11/14 features and for "old-school" C++ developers will not even read like C++ anymore.Specifically, it uses:- lambda functions (C++11) with generalized capture semantics (C++14)- rvalue references (C++11)- auto variables (C++11)- decltype and trailing function return type syntax (C++11)- std::move and s…
#include <iostream>
#include <future>
using namespace std;
template <typename Fn, typename... Args>
auto do_async_with_log(ostream& os, Fn&& fn, Args&&... args) ->
os << "[TID=" << this_thread::get_id()
<< "] Starting to invoke function..." << endl;
auto bound = bind(fn, forward<Args&&...>(args...));
return async([b=move(bound),&os]() mutable {
auto result = b();
os << "[TID=" << this_thread::get_id()
<< "] ...invocation done, returning " << result << endl;
return result;

This comment has been minimized.

Copy link

Jesbus commented Aug 15, 2015

Wow. This functions shows me that I haven't even started learning modern C++ yet.


This comment has been minimized.

Copy link

pmalek commented Aug 15, 2015

Simply... wow...
@goldshtn: can you show a usage of that function?


This comment has been minimized.

Copy link

jepio commented Aug 16, 2015

@pmalek pass it an ostream, a functor and arguments and it will execute:

auto check_answer = [](int x) { return x == 42; };
auto future_answer = do_async_with_log(cout, check_answer, 41);
return future_answer.get();

But I do have a few comments.

  • On line 12 the correct syntax is forward<Args>(args)...

  • async has this kind of bind functionality built-in so I would consider using it:

    return async([fn = forward<Fn>(fn), &os](auto&&... args) {
        auto result = fn(forward<decltype(args)>(args)...);
        os << ...
        return result;
    }, forward<Args>(args)...);

But on second thought it seems that bind minimizes the amount of forward spam, so good job on thinking of that one.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.