StarMirror/CppCoreGuidelines
1
0
Fork 0
mirror of https://github.com/isocpp/CppCoreGuidelines.git synced 2024-03-22 13:30:58 +08:00
Code Issues Projects Releases Wiki Activity

R.34-35 shared_ptr examples (#1808)

Browse Source
This commit is contained in:
bgloyer 2021-08-29 11:01:17 -07:00 committed by GitHub
parent ddc8f3e7d6
commit 375d452495
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 18 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
CppCoreGuidelines.md
View File

@ -9135,7 +9135,7 @@ Here, we ignore such cases.
* [R.31: If you have non-`std` smart pointers, follow the basic pattern from `std`](#Rr-smart)
* [R.32: Take a `unique_ptr<widget>` parameter to express that a function assumes ownership of a `widget`](#Rr-uniqueptrparam)
* [R.33: Take a `unique_ptr<widget>&` parameter to express that a function reseats the `widget`](#Rr-reseat)
* [R.34: Take a `shared_ptr<widget>` parameter to express that a function is part owner](#Rr-sharedptrparam-owner)
* [R.34: Take a `shared_ptr<widget>` parameter to express shared ownership](#Rr-sharedptrparam-owner)
* [R.35: Take a `shared_ptr<widget>&` parameter to express that a function might reseat the shared pointer](#Rr-sharedptrparam)
* [R.36: Take a `const shared_ptr<widget>&` parameter to express that it might retain a reference count to the object ???](#Rr-sharedptrparam-const)
* [R.37: Do not pass a pointer or reference obtained from an aliased smart pointer](#Rr-smartptrget)
@ -9810,7 +9810,7 @@ Using `unique_ptr` in this way both documents and enforces the function call's r
* (Simple) Warn if a function takes a `Unique_pointer<T>` parameter by lvalue reference and does not either assign to it or call `reset()` on it on at least one code path. Suggest taking a `T*` or `T&` instead.
* (Simple) ((Foundation)) Warn if a function takes a `Unique_pointer<T>` parameter by reference to `const`. Suggest taking a `const T*` or `const T&` instead.
### <a name="Rr-sharedptrparam-owner"></a>R.34: Take a `shared_ptr<widget>` parameter to express that a function is part owner
### <a name="Rr-sharedptrparam-owner"></a>R.34: Take a `shared_ptr<widget>` parameter to express shared ownership
##### Reason
@ -9818,11 +9818,16 @@ This makes the function's ownership sharing explicit.
##### Example, good
void share(shared_ptr<widget>); // share -- "will" retain refcount
void may_share(const shared_ptr<widget>&); // "might" retain refcount
void reseat(shared_ptr<widget>&); // "might" reseat ptr
class WidgetUser
{
public:
// WidgetUser will share ownership of the widget
explicit WidgetUser(std::shared_ptr<widget> w) noexcept:
m_widget{std::move(w)} {}
// ...
private:
std::shared_ptr<widget> m_widget;
};
##### Enforcement
@ -9842,11 +9847,11 @@ This makes the function's reseating explicit.
##### Example, good
void share(shared_ptr<widget>); // share -- "will" retain refcount
void reseat(shared_ptr<widget>&); // "might" reseat ptr
void may_share(const shared_ptr<widget>&); // "might" retain refcount
void ChangeWidget(std::shared_ptr<widget>& w)
{
// This will change the callers widget
w = std::make_shared<widget>(widget{});
}
##### Enforcement

1
scripts/hunspell/isocpp.dic
View File

@ -646,6 +646,7 @@ webby
Webcolor
webcolors
WG21
WidgetUser
WorkQueue
'widen'
x1