When is it good to use pass by reference in PHP?

Question

In C++ if you pass a large array to a function, you need to pass it by reference, so that it is not copied to the new function wasting memory. If you don\'t want it modifie

Answer 1

In PHP :

• objects are passed by reference¹ -- always
• arrays and scalars are passed by value by default ; and can be passed by reference, using an & in the function's declaration.

For the performance part of your question, PHP doesn't deal with that the same way as C/C++ ; you should read the following article : Do not use PHP references

^1. _{Or that's what we usually say -- even if it's not "completely true" -- see Objects and references}