(C++) noexcept

noexcept is a keyword to indicate that a function may not throw an exception. If the function does throw an exception, std::terminate is called.

Example

• noexcept example 1: basics

Advice

• If a function may not throw, declare it noexcept [1]
• Generated destructors are implicitly noexcept, as destructors should not throw [2]
• A generated copy or move operation is implicitly noexcept if all of the copy or move operations it uses on members of its class have noexcept destructors [3]. Declare a move operation noexcept, as it should not throw [3]
• Reserve noexcept for functions with wide interfaces [4]
• noexcept matters [5]

References

• [1] Bjarne Stroustrup. The C++ Programming Language (4th edition). 2013. ISBN: 978-0-321-56384-2. Chapter 13.7. Advice, page 387: '[23] If your function may not throw, declare it noexcept'
• [2] Bjarne Stroustrup's C++11 FAQ: 'A destructor shouldn't throw; a generated destructor is implicitly noexcept (independently of what code is in its body) if all of the members of its class have noexcept destructors.'
• [3] Bjarne Stroustrup's C++11 FAQ: 'It is typically a bad idea to have a move operation throw, so declare those noexcept whereever possible. A generated copy or move operation is implicitly noexcept if all of the copy or move operations it uses on members of its class have noexcept destructors.'
• [4] Scott Meyers. C++ And Beyond 2012 session: 'Initial thoughts on Effective C++11'. 2012. 'Reserve noexcept for Functions with Wide Interfaces'
• [5] Jason Turner. C++ Weekly - Ep 109 - When noexcept Really Matters