What does this variadic template code do?

Question

template  
void for_each_argument(F f, Args&&... args) { 
    [](...){}((f(std::forward(args)), 0)...); 
}
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Answer 1

Actually it calls function f for each argument in args in unspecified order.

[](...){}

create lambda function, that does nothing and receives arbitrary number of arguments (va args).

((f(std::forward(args)), 0)...)

argument of lambda.

(f(std::forward(args)), 0)

call f with forwarded argument, send 0 to lambda.

If you want specified order you can use following thing:

using swallow = int[];
(void)swallow{0, (f(std::forward(args)), 0)...};