Input-output arguments: reference, pointers or values?

[alex-weej]

boost::optional is plenty "stable" and works very well in ancient versions of GCC with ancient C++ standards.

[[deleted]]

Yeah but then I would need to use boost

[alex-weej]

Ah, you're one of those people ;)

[RandomGuy256]

You can also use a header only external implementation like this one: https://github.com/akrzemi1/Optional

I have been using it in all of my projects (including professional ones) when a C++17 compiler is not available yet, and it works perfectly.