NAME¶

std::assignable_from - std::assignable_from

Synopsis¶

Defined in header <concepts>
template< class LHS, class RHS >

concept assignable_from =
std::is_lvalue_reference_v<LHS> &&
std::common_reference_with<
const std::remove_reference_t<LHS>&, (since C++20)
const std::remove_reference_t<RHS>&> &&
requires(LHS lhs, RHS&& rhs) {
{ lhs = std::forward<RHS>(rhs) } -> std::same_as<LHS>;

};

The concept assignable_from<LHS, RHS> specifies that an expression of the type and
value category specified by RHS can be assigned to an lvalue expression whose type
is specified by LHS.

Notes¶

Assignment need not be a total function. In particular, if assigning to some object
x can cause some other object y to be modified, then x = y is likely not in the
domain of =. This typically happens if the right operand is owned directly or
indirectly by the left operand (e.g., with smart pointers to nodes in a node-based
data structure, or with something like std::vector<std::any>).

See also¶

is_assignable
is_trivially_assignable checks if a type has an assignment operator for a specific
is_nothrow_assignable argument
(C++11) (class template)
(C++11)
(C++11)