Difference between revisions of "cpp/named req/CopyAssignable"
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| − | {{cpp/ | + | {{cpp/named req/title|CopyAssignable}} |
| − | {{cpp/ | + | {{cpp/named req/navbar}} |
| − | Specifies that an instance of the type can be copy-assigned | + | Specifies that an instance of the type can be copy-assigned from an [[cpp/language/value_category|lvalue expression]]. |
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===Requirements=== | ===Requirements=== | ||
| + | The type {{tt|T}} satisfies {{named req/core|CopyAssignable}} if | ||
| + | * The type {{tt|T}} satisfies {{named req|MoveAssignable}}, and | ||
| + | Given | ||
| + | * {{tt|t}}, a modifiable [[cpp/language/value_category|lvalue expression]] of type {{tt|T}}, | ||
| + | * {{tt|v}}, an [[cpp/language/value_category|lvalue]] expression of type {{tt|T}} or {{tt|const T}} or an [[cpp/language/value_category|rvalue]] expression of type {{tt|const T}}. | ||
| − | The | + | The following expressions must be valid and have their specified effects. |
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| − | { | + | {|table class=wikitable |
| − | + | |- | |
| − | + | !Expression||Return type||Return value||Post-conditions | |
| − | + | |- | |
| − | + | |{{c|1=t = v}} | |
| + | |{{tt|T&}} | ||
| + | |{{tt|t}} | ||
| + | |The value of {{tt|t}} is equivalent to the value of {{tt|v}}. | ||
| + | The value of {{tt|v}} is unchanged. | ||
| + | |} | ||
===See also=== | ===See also=== | ||
| − | {{ | + | {{dsc begin}} |
| − | {{ | + | {{dsc inc|cpp/types/dsc is_copy_assignable}} |
| − | {{ | + | {{dsc inc|cpp/concepts/dsc assignable_from}} |
| + | {{dsc end}} | ||
| − | + | {{langlinks|de|es|fr|it|ja|pt|ru|zh}} | |
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Latest revision as of 10:36, 8 August 2023
Specifies that an instance of the type can be copy-assigned from an lvalue expression.
[edit] Requirements
The type T satisfies CopyAssignable if
- The type
Tsatisfies MoveAssignable, and
Given
-
t, a modifiable lvalue expression of typeT, -
v, an lvalue expression of typeTorconst Tor an rvalue expression of typeconst T.
The following expressions must be valid and have their specified effects.
| Expression | Return type | Return value | Post-conditions |
|---|---|---|---|
| t = v | T&
|
t
|
The value of t is equivalent to the value of v.
The value of |
[edit] See also
| (C++11)(C++11)(C++11) |
checks if a type has a copy assignment operator (class template) |
| (C++20) |
specifies that a type is assignable from another type (concept) |
