◆ uninitialized_copy() [2/2]

template<typename InputIterator , typename ForwardIterator >
ForwardIterator thrust::uninitialized_copy ( InputIterator  first,
InputIterator  last,
ForwardIterator  result 

In thrust, the function thrust::device_new allocates memory for an object and then creates an object at that location by calling a constructor. Occasionally, however, it is useful to separate those two operations. If each iterator in the range [result, result + (last - first)) points to uninitialized memory, then uninitialized_copy creates a copy of [first, last) in that range. That is, for each iterator i in the input, uninitialized_copy creates a copy of *i in the location pointed to by the corresponding iterator in the output range by ForwardIterator's value_type's copy constructor with *i as its argument.

firstThe first element of the input range to copy from.
lastThe last element of the input range to copy from.
resultThe first element of the output range to copy to.
An iterator pointing to the last element of the output range.
Template Parameters
InputIteratoris a model of Input Iterator.
ForwardIteratoris a model of Forward Iterator, ForwardIterator is mutable, and ForwardIterator's value_type has a constructor that takes a single argument whose type is InputIterator's value_type.
first may equal result, but the range [first, last) and the range [result, result + (last - first)) shall not overlap otherwise.

The following code snippet demonstrates how to use uninitialized_copy to initialize a range of uninitialized memory.

struct Int
__host__ __device__
Int(int x) : val(x) {}
int val;
const int N = 137;
Int val(46);
thrust::device_ptr<Int> array = thrust::device_malloc<Int>(N);
thrust::uninitialized_copy(input.begin(), input.end(), array);
// Int x = array[i];
// x.val == 46 for all 0 <= i < N
See also