What is the keyword noexcept for and when to use it?

Question

What does the keyword noexcept in C++ and in what situation it should be used?

Answer 1

Two forms:

Specification attribute

Indicates that the function can not launch an exception, which allows a series of optimizations and the compiler better understand the semantics. After that put can not take, is part of the contract. use it whenever possible. In fact until a new form of exception comes, in C++20 or C++23, avoid exceptions.

In C++14 it was a little different, but do not consider this form, prefer the C++17.

See more on documentation.

Operator

Used essentially for metaprogramming/reflection enabling selections and specializations than compiling as to what to find. Something much more advanced. It is a way to query during the build if the function can not launch exception.

See more on documentation.