std::remove_cv, std::remove_const, std::remove_volatile
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<tbody> </tbody>| Elemento definito nell'header <type_traits>
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template< class T > struct remove_cv; |
(1) | (dal C++11) |
template< class T > struct remove_const; |
(2) | (dal C++11) |
template< class T > struct remove_volatile; |
(3) | (dal C++11) |
Provides the member typedef type which is the same as T, except that its topmost cv-qualifiers are removed.
1) removes the topmost const, the topmost volatile, or both, if present.
2) removes the topmost const
3) removes the topmost volatile
Membri tipi
Nome
Original: Name The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
Definition |
type
|
the type T without cv-qualifier
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Possibile implementazione
template< class T >
struct remove_cv {
typedef typename std::remove_volatile<typename std::remove_const<T>::type>::type type;
};
template< class T > struct remove_const { typedef T type; };
template< class T > struct remove_const<const T> { typedef T type; };
template< class T > struct remove_volatile { typedef T type; };
template< class T > struct remove_volatile<volatile T> { typedef T type; };
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Esempio
Removing const/volatile from const volatile int * does not modify the type, because the pointer itself is neither const nor volatile.
#include <iostream>
#include <type_traits>
int main() {
typedef std::remove_cv<const int>::type type1;
typedef std::remove_cv<volatile int>::type type2;
typedef std::remove_cv<const volatile int>::type type3;
typedef std::remove_cv<const volatile int*>::type type4;
typedef std::remove_cv<int * const volatile>::type type5;
std::cout << "test1 " << (std::is_same<int, type1>::value
? "passed" : "failed") << '\n';
std::cout << "test2 " << (std::is_same<int, type2>::value
? "passed" : "failed") << '\n';
std::cout << "test3 " << (std::is_same<int, type3>::value
? "passed" : "failed") << '\n';
std::cout << "test4 " << (std::is_same<const volatile int*, type4>::value
? "passed" : "failed") << '\n';
std::cout << "test5 " << (std::is_same<int*, type5>::value
? "passed" : "failed") << '\n';
}
Output:
test1 passed
test2 passed
test3 passed
test4 passed
test5 passed
Vedi anche
(C++11) |
controlla se è un tipo const qualificati Original: checks if a type is const-qualified The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe template) |
(C++11) |
controlla se è un tipo di volatili qualificato Original: checks if a type is volatile-qualified The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (classe template) |