Issue 2873: Add noexcept to several shared_ptr related functions

Title: Add noexcept to several shared_ptr related functions
Status: c++17
Section: [util.smartptr.shared]
Submitter: United States

Created on 2017-02-03.00:00:00 last changed 90 months ago

Messages

Date: 2017-03-03.22:08:49

Proposed resolution:

This wording is relative to N4640.

Modify [util.smartptr.shared] as indicated:

  template<class U> bool owner_before(const shared_ptr<U>& b) const noexcept;
  template<class U> bool owner_before(const weak_ptr<U>& b) const noexcept;

Modify [util.smartptr.shared.obs] as indicated:

template<class U> bool owner_before(const shared_ptr<U>& b) const noexcept;
template<class U> bool owner_before(const weak_ptr<U>& b) const noexcept;

Modify [util.smartptr.ownerless] as indicated:

template<class T> struct owner_less<shared_ptr<T>> {
   bool operator()(const shared_ptr<T>&, const shared_ptr<T>&) const noexcept;
   bool operator()(const shared_ptr<T>&, const weak_ptr<T>&) const noexcept;
   bool operator()(const weak_ptr<T>&, const shared_ptr<T>&) const noexcept;
};

template<class T> struct owner_less<weak_ptr<T>> {
   bool operator()(const weak_ptr<T>&, const weak_ptr<T>&) const noexcept;
   bool operator()(const shared_ptr<T>&, const weak_ptr<T>&) const noexcept;
   bool operator()(const weak_ptr<T>&, const shared_ptr<T>&) const noexcept;
};

template<> struct owner_less<void> {
   template<class T, class U>
      bool operator()(const shared_ptr<T>&, const shared_ptr<U>&) const noexcept;
   template<class T, class U>
      bool operator()(const shared_ptr<T>&, const weak_ptr<U>&) const noexcept;
   template<class T, class U>
      bool operator()(const weak_ptr<T>&, const shared_ptr<U>&) const noexcept;
   template<class T, class U>
      bool operator()(const weak_ptr<T>&, const weak_ptr<U>&) const noexcept;
   using is_transparent = unspecified;
};

msg8960 (view)

Date: 2017-03-03.22:08:49

[ Kona 2017-02-27 ]

Accepted as Immediate to resolve NB comment.

msg8959 (view)

Date: 2017-02-15.00:00:00

[ 2017-02-20, Marshall adds wording ]

msg8862 (view)

Date: 2017-02-03.00:00:00

Addresses US 124

Several shared_ptr related functions have wide contracts and cannot throw, so should be marked unconditionally noexcept.

Proposed change:

Add noexcept to:

template<class U> 
bool 
shared_ptr::owner_before(shared_ptr<U> const& b) const noexcept;
 
template<class U> 
bool 
shared_ptr::owner_before(weak_ptr<U> const& b) const noexcept;

template<class U> 
bool  
weak_ptr::owner_before(shared_ptr<U> const& b) const noexcept; 

template<class U> 
bool
weak_ptr::owner_before(weak_ptr<U> const& b) const noexcept;
 
bool owner_less::operator()(A,B) const noexcept; // all versions

History
Date	User	Action	Args
2017-07-30 20:15:43	admin	set	status: wp -> c++17
2017-03-05 23:46:08	admin	set	status: immediate -> wp
2017-03-03 22:08:49	admin	set	messages: + msg9055
2017-03-03 22:08:49	admin	set	status: new -> immediate
2017-02-20 20:55:10	admin	set	messages: + msg8960
2017-02-20 20:55:10	admin	set	messages: + msg8959
2017-02-03 00:00:00	admin	create