3 Terms and definitions [intro.defs]


⟨library⟩ expressions that all have the same effects, either are all potentially-throwing or are all not potentially-throwing, and either are all constant subexpressions or are all not constant subexpressions
[Example 1:
For a value x of type int and a function f that accepts integer arguments, the expressions f(x + 2), f(2 + x), and f(1 + x + 1) are expression-equivalent.
— end example]