Difference between revisions of "cpp/named req/CopyAssignable"
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Specifies that an instance of the type can be copy-assigned from an [[cpp/language/value_category|lvalue expression]]. | Specifies that an instance of the type can be copy-assigned from an [[cpp/language/value_category|lvalue expression]]. | ||
===Requirements=== | ===Requirements=== | ||
| − | + | The type {{tt|T}} satisfies {{named req/core|CopyAssignable}} if | |
| − | The type {{tt|T}} satisfies {{ | + | * The type {{tt|T}} satisfies {{named req|MoveAssignable}}, and |
| − | + | ||
| − | * The type {{tt|T}} satisfies {{ | + | |
| − | + | ||
Given | Given | ||
| − | * {{tt|t}}, a modifiable [[cpp/language/value_category|lvalue expression]] of type {{tt|T}} | + | * {{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}} | + | * {{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 following expressions must be valid and have their specified effects | + | The following expressions must be valid and have their specified effects. |
{|table class=wikitable | {|table class=wikitable | ||
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!Expression||Return type||Return value||Post-conditions | !Expression||Return type||Return value||Post-conditions | ||
|- | |- | ||
| − | | {{c|1=t = v}} | + | |{{c|1=t = v}} |
| − | | {{tt|T&}} | + | |{{tt|T&}} |
| − | | {{tt|t}} | + | |{{tt|t}} |
| − | | The value of {{tt|t}} is equivalent to the value of {{tt|v}}. | + | |The value of {{tt|t}} is equivalent to the value of {{tt|v}}. |
The value of {{tt|v}} is unchanged. | The value of {{tt|v}} is unchanged. | ||
|} | |} | ||
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===See also=== | ===See also=== | ||
{{dsc begin}} | {{dsc begin}} | ||
| − | {{dsc inc | cpp/types/dsc is_copy_assignable}} | + | {{dsc inc|cpp/types/dsc is_copy_assignable}} |
| + | {{dsc inc|cpp/concepts/dsc assignable_from}} | ||
{{dsc end}} | {{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) |
