16 Library introduction [library]

In certain cases (replacement functions, handler functions, operations on types used to instantiate standard library template components), the C++ standard library depends on components supplied by a C++ program.

If these components do not meet their requirements, this document places no requirements on the implementation.

In particular, the behavior is undefined in the following cases:

• (2.1)
  For replacement functions ([new.delete]), if the installed replacement function does not implement the semantics of the applicable Required behavior: paragraph.
• (2.2)
  For handler functions ([new.handler], [terminate.handler]), if the installed handler function does not implement the semantics of the applicable Required behavior: paragraph.
• (2.3)
  For types used as template arguments when instantiating a template component, if the operations on the type do not implement the semantics of the applicable Requirements subclause ([allocator.requirements], [container.requirements], [iterator.requirements], [algorithms.requirements], [numeric.requirements]).

  Operations on such types can report a failure by throwing an exception unless otherwise specified.
• (2.4)
  If any replacement function or handler function or destructor operation exits via an exception, unless specifically allowed in the applicable Required behavior: paragraph.
• (2.5)
  If an incomplete type ([basic.types.general]) is used as a template argument when instantiating a template component or evaluating a concept, unless specifically allowed for that component.