Namespaces
Variants
Views
Actions

std::experimental::ranges::ConvertibleTo

From cppreference.com
< cpp‎ | experimental‎ | ranges
 
 
Technical specifications
Filesystem library (filesystem TS)
Library fundamentals (library fundamentals TS)
Library fundamentals 2 (library fundamentals 2 TS)
Extensions for parallelism (parallelism TS)
Extensions for concurrency (concurrency TS)
Concepts (concepts TS)
Ranges (ranges TS)
Special mathematical functions (special math TR)
 
 
Concepts library
Core language concepts
ConvertibleTo
                              
Object concepts
                              
                              
Comparison concepts
Callable concepts
                                        
                              
URNG concept
 
template <class From, class To>

concept bool ConvertibleTo =
  std::is_convertible<From, To>::value &&
  requires(From (&f)()) {
    static_cast<To>(f());

  };
(ranges TS)

The concept ConvertibleTo<From, To> specifies that an expression of the type and value category specified by From can be implicitly and explicitly converted to the type To, and the two forms of conversion are equivalent.

Specifically, ConvertibleTo<From, To> is satisfied only if, given the invented function To test(From (&f)()) { return f(); } and a function F of type From () such that the expression F() is equality-preserving,

  • Either
    • To is neither an object type nor a reference-to-object type, or
    • static_cast<To>(f()) is equal to test(f), and
  • One of the following is true:
    • From is not a reference-to-object type, or
    • From is an rvalue reference to a non-const-qualified type, and the resulting state of the object referenced by f() is valid but unspecified after either expression above; or
    • the object referred to by f() is not modified by either expression above.

There need not be any subsumption relationship between ConvertibleTo<From, To> and std::is_convertible<From, To>::value.

[edit] See also

checks if a type can be converted to the other type
(class template) [edit]