std::is_destructible, std::is_trivially_destructible, std::is_nothrow_destructible
Defined in header
<type_traits>
|
||
template< class T >
struct is_destructible; |
(1) | (since C++11) |
template< class T >
struct is_trivially_destructible; |
(2) | (since C++11) |
template< class T >
struct is_nothrow_destructible; |
(3) | (since C++11) |
1) If an imaginary struct containing a member object of type T has a non-deleted destructor, provides the member constant value equal true. For any other type, value is false. |
(until C++14) |
1) If If If |
(since C++14) |
2) same as 1), but the destructor does not call any operation that is not trivial.
3) same as 1), but the destructor is noexcept.
Contents |
Inherited from std::integral_constant
Member constants
value
[static]
|
true if T is destructible, false otherwise (public static member constant) |
Member functions
operator bool |
converts the object to bool, returns value (public member function) |
operator()
(C++14)
|
returns value (public member function) |
Member types
Type | Definition |
value_type
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bool
|
type
|
std::integral_constant<bool, value> |
[edit] Notes
Because the C++ program terminates if a destructor throws an exception during stack unwinding (which usually cannot be predicted), all practical destructors are non-throwing even if they are not declared noexcept. All destructors found in the C++ standard library are non-throwing.
Storage occupied by trivially destructible objects may be reused without calling the destructor.
[edit] Example
#include <iostream> #include <string> #include <type_traits> struct Foo { std::string str; ~Foo() noexcept {}; }; struct Bar { ~Bar() = default; }; int main() { std::cout << std::boolalpha << "std::string is destructible? " << std::is_destructible<std::string>::value << '\n' << "Foo is nothrow destructible? " << std::is_nothrow_destructible<Foo>::value << '\n' << "Bar is trivally destructible? " << std::is_trivially_destructible<Bar>::value << '\n'; }
Output:
std::string is destructible? true Foo is nothrow destructible? true Bar is trivally destructible? true
[edit] See also
(C++11)(C++11)(C++11)
|
checks if a type has a constructor for specific arguments (class template) |
(C++11)
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checks if a type has a virtual destructor (class template) |
(library fundamentals TS)
|
variable template alias of std::is_destructible::value (variable template) |
(library fundamentals TS)
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variable template alias of std::is_trivially_destructible::value (variable template) |
(library fundamentals TS)
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variable template alias of std::is_nothrow_destructible::value (variable template) |