In Kopfzeile definiert <memory>
template< class InputIt, class ForwardIt >
ForwardIt uninitialized_copy( InputIt first, InputIt last, ForwardIt d_first );
(1)
template< class ExecutionPolicy, class InputIt, class ForwardIt >
ForwardIt uninitialized_copy( ExecutionPolicy&& policy, InputIt first, InputIt last, ForwardIt d_first );
(2) (seit C++17)

1) Kopiert Elemente aus dem Sortiment [first, last) to an uninitialized memory area beginning at d_first as if by

for (; first != last; ++d_first, (void) ++first)
   ::new (static_cast<void*>(std::addressof(*d_first)))
      typename std::iterator_traits<ForwardIt>::value_type(*first);

If an exception is thrown during the initialization, the objects already constructed are destroyed in an unspecified order.
2) Same as (1), but executed according to policy. This overload does not participate in overload resolution unless std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is true

Parameters

first, last - the range of the elements to copy
d_first - the beginning of the destination range
policy - the execution policy to use. See execution policy for details.
Type requirements
-InputIt must meet the requirements of LegacyInputIterator.
-ForwardIt must meet the requirements of LegacyForwardIterator.
-No increment, assignment, comparison, or indirection through valid instances of ForwardIt may throw exceptions.

Return value

Iterator to the element past the last element copied.

Complexity

Linear in the distance between first and last.

Exceptions

The overload with a template parameter named ExecutionPolicy reports errors as follows:

  • If execution of a function invoked as part of the algorithm throws an exception and ExecutionPolicy is one of the standard policies, std::terminate is called. For any other ExecutionPolicy, the behavior is implementation-defined.
  • If the algorithm fails to allocate memory, std::bad_alloc is thrown.

Possible implementation

template<class InputIt, class ForwardIt>
ForwardIt uninitialized_copy(InputIt first, InputIt last, ForwardIt d_first)
{
    typedef typename std::iterator_traits<ForwardIt>::value_type Value;
    ForwardIt current = d_first;
    try {
        for (; first != last; ++first, (void) ++current) {
            ::new (static_cast<void*>(std::addressof(*current))) Value(*first);
        }
        return current;
    } catch (...) {
        for (; d_first != current; ++d_first) {
            d_first->~Value();
        }
        throw;
    }
}

Example

#include <iostream>
#include <memory>
#include <cstdlib>
#include <string>
 
int main()
{
    const char *v[] = {"Dies", "ist", "ein", "Beispiel"};
 
    Auto Größe = std::Größe(v);
 
    wenn(Leere *pbuf = std::ausgerichtet_alloc(ausrichten(std::Schnur), Größe von(std::Schnur) * Größe))
    {
        Versuchen
        {
            Auto Erste = static_cast<std::Schnur*>(pbuf);
            Auto letzte = std::uninitialized_copy(std::Start(v), std::Ende(v), Erste);
 
            zum (Auto es = Erste; es != letzte; ++es)
                std::cout < *es < '_';
 
            std::zerstören(Erste, letzte);
        }
        fangen(...) {}
        std::kostenlos(pbuf);
    }
}

Ausgabe:

This_is_an_example_

Siehe auch

uninitialized_copy_n
(C++11)
kopiert eine Reihe von Objekten in einen nicht initialisierten Speicherbereich
(Funktionsvorlage)