C++11 QString pass by reference?

[wooyay]

Hi all,
I am starting a Qt5 project where I want to use C++11 exclusively.
Which is faster for QStrings now, pass by value or pass by reference?

Cheers,
Martin

[sierdzio]

QString is implicitly shared, so it's quite fast either way. You can benchmark if you prefer, I guess passing by reference would be a little bit faster, but probably not that much.

[JKSH]

Here's an article for more details: http://qt-project.org/doc/qt-5.0/qtcore/implicit-sharing.html

As sierdzio said, there's probably no noticeable difference between passing by value or passing by reference, because QString is very highly optimized already

[stereomatching]

I always pass by reference because of two reasons

1 : pass by reference don't need to take the price of reference count
2 : it is more natural since the stl containers do not ask to use reference count technique,
many c++ programmers may feel weird when they see you pass by value rather than pass by reference.