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Document weak_ptr aliasing constructors and empty

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This commit is contained in:
Peter Dimov
2019-04-21 22:52:44 +03:00
parent 78e095d761
commit 016e682af6
2 changed files with 33 additions and 2 deletions
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3
doc/smart_ptr/shared_ptr.adoc
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@ -132,7 +132,6 @@ namespace boost {
template<class Y> shared_ptr(shared_ptr<Y> && r) noexcept;
template<class Y> shared_ptr(shared_ptr<Y> const & r, element_type * p) noexcept;
template<class Y> shared_ptr(shared_ptr<Y> && r, element_type * p) noexcept;
template<class Y> explicit shared_ptr(weak_ptr<Y> const & r);
@ -373,7 +372,7 @@ template<class Y> shared_ptr(shared_ptr<Y> const & r, element_type * p) noexcept
[none]
* {blank}
+
Effects:: constructs a `shared_ptr` that shares ownership with `r` and stores `p`.
Effects:: Copy-constructs a `shared_ptr` from `r`, while storing `p` instead.
Postconditions:: `get() == p && use_count() == r.use_count()`.

32
doc/smart_ptr/weak_ptr.adoc
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@ -88,6 +88,10 @@ namespace boost {
weak_ptr(weak_ptr && r) noexcept;
template<class Y> weak_ptr(shared_ptr<Y> const & r, element_type * p) noexcept;
template<class Y> weak_ptr(weak_ptr<Y> const & r, element_type * p) noexcept;
template<class Y> weak_ptr(weak_ptr<Y> && r, element_type * p) noexcept;
~weak_ptr() noexcept;
weak_ptr & operator=(weak_ptr const & r) noexcept;
@ -98,6 +102,8 @@ namespace boost {
long use_count() const noexcept;
bool expired() const noexcept;
bool empty() const noexcept;
shared_ptr<T> lock() const noexcept;
void reset() noexcept;
@ -157,6 +163,21 @@ weak_ptr(weak_ptr && r) noexcept;
Effects:: Constructs a `weak_ptr` that has the value `r` held.
Postconditions:: `r` is empty.
### aliasing constructors
```
template<class Y> weak_ptr(shared_ptr<Y> const & r, element_type * p) noexcept;
```
```
template<class Y> weak_ptr(weak_ptr<Y> const & r, element_type * p) noexcept;
```
```
template<class Y> weak_ptr(weak_ptr<Y> && r, element_type * p) noexcept;
```
Effects:: Constructs a `weak_ptr` from `r` as if by using the corresponding converting/copy/move constructor, but stores `p` instead.
Postconditions:: `use_count() == r.use_count()`. When `!expired()`, `shared_ptr<T>(*this).get() == p`.
NOTE: These constructors are an extension, not present in `std::weak_ptr`.
### destructor
```
~weak_ptr() noexcept;
@ -204,6 +225,17 @@ bool expired() const noexcept;
+
Returns:: `use_count() == 0`.
### empty
```
bool empty() const noexcept;
```
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* {blank}
+
Returns:: `true` when `*this` is empty, `false` otherwise.
NOTE: This function is an extension, not present in `std::weak_ptr`.
### lock
```
shared_ptr<T> lock() const noexcept;