Issue 2873: Add noexcept to several shared_ptr related functions (original) (raw)

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Section: 20.3.2.2 [util.smartptr.shared] Status: C++17 Submitter: United States Opened: 2017-02-03 Last modified: 2020-09-06

Priority: Not Prioritized

View all other issues in [util.smartptr.shared].

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Discussion:

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 bool shared_ptr::owner_before(shared_ptr const& b) const noexcept;

template bool shared_ptr::owner_before(weak_ptr const& b) const noexcept;

template bool
weak_ptr::owner_before(shared_ptr const& b) const noexcept;

template bool weak_ptr::owner_before(weak_ptr const& b) const noexcept;

bool owner_less::operator()(A,B) const noexcept; // all versions

[2017-02-20, Marshall adds wording]

[Kona 2017-02-27]

Accepted as Immediate to resolve NB comment.

Proposed resolution:

This wording is relative to N4640.

  1. Modify 20.3.2.2 [util.smartptr.shared] as indicated:

    template bool owner_before(const shared_ptr& b) const noexcept;
    template bool owner_before(const weak_ptr& b) const noexcept;

  2. Modify 20.3.2.2.6 [util.smartptr.shared.obs] as indicated:

    template bool owner_before(const shared_ptr& b) const noexcept;
    template bool owner_before(const weak_ptr& b) const noexcept;

  3. Modify 20.3.2.4 [util.smartptr.ownerless] as indicated:

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

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

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

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