This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 110b. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2023-01-15


1916. “Same cv-unqualified type”

Section: 11.4.5.3  [class.copy.ctor]     Status: CD4     Submitter: Richard Smith     Date: 2014-04-18

[Moved to DR at the May, 2015 meeting.]

11.4.5.3 [class.copy.ctor] paragraph 31 uses the phrase, “same cv-unqualified type,” twice. This is ambiguous, potentially either requiring that the types not be cv-qualified or meaning that cv-qualification should be ignored. The latter meaning is intended and the phrase should be replaced accordingly.

Proposed resolution (November, 2014):

Change 11.4.5.3 [class.copy.ctor] paragraph 31 as follows:

...This elision of copy/move operations, called copy elision, is permitted in the following circumstances (which may be combined to eliminate multiple copies):

  1. in a return statement in a function with a class return type, when the expression expression is the name of a non-volatile automatic object (other than a function or catch-clause parameter or a variable introduced by the exception-declaration of a handler (14.4 [except.handle])) with the same cv-unqualified type (ignoring cv-qualification) as the function return type, the copy/move operation can be omitted by constructing the automatic object directly into the function's return value

  2. in a throw-expression...

  3. when a temporary class object that has not been bound to a reference (6.7.7 [class.temporary]) would be copied/moved to a class object with the same cv-unqualified type (ignoring cv-qualification), the copy/move operation can be omitted by constructing the temporary object directly into the target of the omitted copy/move

  4. when the exception-declaration...