17 Library introduction [library]

17.3 Definitions [definitions]

17.3.20 replacement function [defns.replacement]

a non-reserved function whose definition is provided by a C++ program
Note: Only one definition for such a function is in effect for the duration of the program's execution, as the result of creating the program ([lex.phases]) and resolving the definitions of all translation units ([basic.link]).  — end note ]