Are the days of passing const std::string & as a parameter over?

📝 Are the Days of Passing const std::string & as a Parameter Over? 🤔

Have you heard the recent talk by Herb Sutter discussing whether the days of passing const std::string & as a parameter are over? 🎙️ If not, let me bring you up to speed! 👉🏼

During his talk, Herb Sutter suggested that the reasons for passing std::vector and std::string by const & are largely gone. Instead, he proposed using a function like this:

std::string do_something(std::string inval)
{
   std::string return_val;
   // ... do stuff ...
   return return_val;
}

Now, you might be scratching your head and wondering why this approach is preferable. After all, inval is much larger than the size of a reference, which is usually implemented as a pointer. Let me break it down for you. 🤓

🔍 Understanding the rationale: The key concept here is that return_val is considered an rvalue at the point the function returns. This means it can be efficiently returned using move semantics, which are very cheap. On the other hand, inval still holds the larger data of the original std::string. 📚

🔁 Leveraging move semantics: When using move semantics, the contents of an object can be moved from one place to another without making a copy. In the case of return_val, it can be efficiently moved out of the function and back to the caller. This eliminates unnecessary copying and improves performance. 💨

📉 The overhead myth: The concern about the size of inval being larger than a reference is valid, but it's important to realize that the cost of copying a small object like a reference is usually negligible. Additionally, passing larger objects by value allows for potential optimizations through copy elision or move construction. So, the overhead of passing larger objects by value is often not as detrimental as it might seem at first glance. 📊

🤔 Why Herb might have suggested this: By advocating for passing std::string by value, Herb is promoting a more modern and efficient coding style. This approach leverages the benefits of move semantics and allows the compiler to make optimizations that can improve performance. It also simplifies the code and reduces the number of parameters being passed around, which in turn enhances readability. 💪

In conclusion, the days of passing const std::string & as a parameter might indeed be over. Though it may initially seem counterintuitive to pass larger objects by value, the benefits of move semantics and potential optimizations make it a viable option. So, why not give it a try? 💡

But hey, I'm curious to hear your thoughts and experiences with this approach! How do you feel about passing std::string by value? Leave a comment below and let's start a discussion! 👇🏼😃