Movatterモバイル変換

This page is a snapshot from the LWG issues list, see theLibrary Active Issues List for more information and the meaning ofCD1 status.

611. Standard library templates and incomplete types

Section: 16.4.5.8[res.on.functions]Status:CD1Submitter: Nicola MusattiOpened: 2006-11-13Last modified: 2016-01-28

Priority:Not Prioritized

View all otherissues in [res.on.functions].

View all issues withCD1 status.

Discussion:

In the latest available draft standard (N2134)§ 17.4.3.6 [res.on.functions] states:

-1- In certain cases (replacement functions, handler functions, operations ontypes used to instantiate standard library template components), the C++Standard Library depends on components supplied by a C++ program. If thesecomponents do not meet their requirements, the Standard places no requirementson the implementation.

-2- In particular, the effects are undefined in the following cases:

[...]

• if an incomplete type (3.9) is used as a template argument wheninstantiating a template component.

This is contradicted by § 20.6.6.2/2 [util.smartptr.shared] whichstates:

[...]

The template parameterT ofshared_ptr may be an incomplete type.

Proposed resolution:

Modify the last bullet of § 17.4.3.6/2 [res.on.functions] to allow forexceptions:

• if an incomplete type (3.9) is used as a template argument wheninstantiating a template component, unless specifically allowed for thecomponent.