Exceptions, with emphasis on C++11 enhancements. Links:

• cppreference.com "Exceptions"
  • throw-expression
  • try-catch block
  • function-try-block
  • noexcept specifier
  • noexcept operator
  • Dynamic exception specification (until C++17)

• Terminate the program.
• Return an error value.
• Return a legal value and leave the program in an “error state” (errno).
• Call an error-handler routine.