std::convertible_to
From cppreference.com
Defined in header <concepts>
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template< class From, class To > concept convertible_to = |
(since C++20) | |
The concept convertible_to<From, To> specifies that an expression of the same type and value category as those of std::declval<From>() can be implicitly and explicitly converted to the type To
, and the two forms of conversion produce equal results.
Contents |
[edit] Semantic requirements
convertible_to<From, To> is modeled only if, given a function fun
of type std::add_rvalue_reference_t<From>() such that the expression fun() is equality-preserving,
- Either
-
To
is neither an object type nor a reference-to-object type, or - static_cast<To>(fun()) is equal to []() -> To { return fun(); }(), and
-
- One of the following is true:
- std::add_rvalue_reference_t<From> is not a reference-to-object type, or
- std::add_rvalue_reference_t<From> is an rvalue reference to a non-const-qualified type, and the resulting state of the object referenced by fun() is valid but unspecified after either expression above; or
- the object referred to by fun() is not modified by either expression above.
[edit] Equality preservation
Expressions declared in requires expressions of the standard library concepts are required to be equality-preserving (except where stated otherwise).
[edit] References
- C++23 standard (ISO/IEC 14882:2024):
- 18.4.4 Concept
convertible_to
[concept.convertible]
- 18.4.4 Concept
- C++20 standard (ISO/IEC 14882:2020):
- 18.4.4 Concept
convertible_to
[concept.convertible]
- 18.4.4 Concept
[edit] See also
(C++11)(C++20) |
checks if a type can be converted to the other type (class template) |