This isn’t just in functional languages. Java, C++, C probably do it too depending on the optimization level.

LOL, what a load of crap -- it is literally the exact opposite -- did you not see the copy constructor that was marked as deleted and how it behaves differently in 11 and 17 ?

@@firstname4337 thatsthejoke.jpg

amazing indeed 😂

Thank you for that imagery 😂

I'm not sure what exactly your objection is here (perhaps you could elaborate?). Yes, the compiler will move returned local variables if a move constructor is available. No move was provided so it called the user-defined copy constructor. Are you saying I should still refer to this as a move even though the copy constructor was called and no move constructor is provided or generated by the compiler? I'm not sure I would agree with calling it a move in that situation, especially not colloquially. Colloquially, when one speaks of eliminating copies and eliminating moves, one is typically referring the act of reducing the number of times the copy constructor or move constructor actually gets called, i.e. an empirical reduction in copies or moves, not a reduction in places where the standard would allow a copy/move. In any case, it is not correct to say that the move constructor "is the copy constructor" if one is not provided. The definition of copy/move constructor in the standard is based on the signature of the function alone. It is *not* based on whether it is called when initializing from a prvalue. Instead, the compiler may chose to copy *instead of* move due to the fact that no move constructor is available.

don't be fooled, it's still horrible to actually code with

@@slpwrm filtered, LMAO

@@slpwrm not true for me. I actually enjoy writing modern C++ than C.

@@drnoob13 I mean yes, but that bar is very low.

If you use the inline keyword or up the optimization level it should, but I'm not an expert on the C++ standard, so don't quote me on that.

A great one to test on compiler explorer! godbolt.org/z/rYq1ejzKW Even in C++23 at -O3 with "if (true)" we still see the copy. Note however that if you move the instantiations of s1, s2 inside the scope of the if block that they are actually returned in, then the copy can be elided because they will no longer interfere with each other.

afaik, the compiler can’t do that - if a function is called ( explicitly ), it must be called. That optimization would mean you would be calling a different function.

What are you implying here?

Hahaha what is your language of choice now?

@@mCoding In my case, I've ditched C++ after learning about Rust, at least for me, Rust is just C++ minus the enormous headaches that came with the language. I was using C++ for only 2-3 months or so, it's kinda funny how I switched languages so quickly.

Nice way to tell the world you're too bad for real languages.

@@mCoding Python.

@@Tibor0991 LOL. I've spent more than a decade with C++, I just got tired of dealing with the pointless obstacles that it puts in the developer's way for no good reason. You've got an "object oriented language" with a "standard library", but you can't use actual objects or types from the standard library in the public interface of your library unless the user happens to use the same compiler? Get outta here.

Same names, different James!

hi mod

The easiest way is to just define your own hash function, for example, for strings you could do: #include #include #include typedef std::pair pair; struct pair_hash { template std::size_t operator() (const std::pair &pair) const { return std::hash()(pair.first) ^ std::hash()(pair.second); } }; int main() { std::unordered_map unordered_map = { {{"C++", "C++11"}, 2011}, {{"C++", "C++14"}, 2014}, {{"C++", "C++17"}, 2017}, {{"Java", "Java 7"}, 2011}, {{"Java", "Java 8"}, 2014}, {{"Java", "Java 9"}, 2017} }; for (auto const &entry: unordered_map) { auto key_pair = entry.first; std::cout

Extend std::hash, if nobody else is going to use your code.

It's the sound a car makes revving its engine!

You caught the reference! I love his videos!

@@mCoding I knew it was a reference because I saw your comment on his video. 😉

Honestly, what he showed is quite irrelevant to how you code in Cpp. Why? Because you would never do what he did here. I can not think of any context this knowledge would be useful.

Why should you make copies, if you did not need one? You understand that some objects might be really heavy to copy right?

@@Kurkkulimu I think he means because you don't have to jump through hoops to avoid unnecessary copying as well as to make the compiler generate optimized code.