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    cpp/named req/CopyAssignable: Difference between revisions

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    ===Requirements===
    ===Requirements===
    The type {{tt|T}} satisfies {{named req/core|CopyAssignable}} if
    The type {{tt|T}} satisfies {{named req/core|CopyAssignable}} if
    * The type {{tt|T}} satisfies {{named req|MoveAssignable}}, and
    * The type {{tt|T}} satisfies {{named req|MoveAssignable}}, and
    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
    Line 20: Line 17:
    !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.
    |}
    |}
    Line 29: Line 26:
    ===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 inc|cpp/concepts/dsc assignable_from}}
    {{dsc end}}
    {{dsc end}}


    {{langlinks|de|es|fr|it|ja|pt|ru|zh}}
    {{langlinks|de|es|fr|it|ja|pt|ru|zh}}

    Latest revision as of 18:36, 8 August 2023

     
    C++
     
    C++ named requirements
     

    Specifies that an instance of the type can be copy-assigned from an lvalue expression.

    Requirements

    The type T satisfies CopyAssignable if

    Given

    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 v is unchanged.

    See also

    (C++11)(C++11)(C++11)
    		 checks if a type has a copy assignment operator
    (class template) [edit]
    (C++20)
    		 specifies that a type is assignable from another type
    (concept) [edit]