17 Library introduction [library]

17.3 Definitions [definitions]

17.3.22 required behavior [defns.required.behavior]

a description of replacement function and handler function semantics applicable to both the behavior provided by the implementation and the behavior of any such function definition in the program
Note: If such a function defined in a C++ program fails to meet the required behavior when it executes, the behavior is undefined.  — end note ]