std::uninitialized_fill

template <class ForwardIterator, class T> void uninitialized_fill (ForwardIterator first, ForwardIterator last, const T& x);

Fill block of memory

Constructs all the elements in the range [first,last) initializing them to a value of x.

Unlike algorithm fill, uninitialized_fill constructs the objects in-place, instead of just copying the value to them. This allows to obtain fully constructed copies into a range of uninitialized memory, such as a memory block obtained by a call to get_temporary_buffer or malloc.

The behavior of this function template is equivalent to:

template < class ForwardIterator, class T >
 void uninitialized_fill ( ForwardIterator first, ForwardIterator last, const T& x )
{
 for (; first!=last; ++first)
 new (static_cast<void*>(&*first))
 typename iterator_traits<ForwardIterator>::value_type(x);
}

Parameters

first, last: Forward iterators to the initial and final positions in an uninitialized sequence. The range affected is [first,last), which contains all the elements between first and last, including the element pointed by first but not the element pointed by last.
x: Value to be used to fill the range.

Return value

none

Example

// uninitialized_fill example
#include <iostream>
#include <memory>
#include <string>
int main () {
 // get block of uninitialized memory:
 std::pair <std::string*,std::ptrdiff_t>
 result = std::get_temporary_buffer<std::string>(3);
 if (result.second>0) {
 std::uninitialized_fill ( result.first, result.first+result.second, "c++ rocks!" );
 for (int i=0; i<result.second; i++)
 std::cout << result.first[i] << '\n';
 std::return_temporary_buffer(result.first);
 }
 return 0;
}

Output:

c++ rocks!
c++ rocks!
c++ rocks!

Complexity

Linear: Constructs (copy constructor) as many objects as the number of elements in the range [first,last).

classes

enum classes

functions

objects

std::uninitialized_fill

Parameters

Return value

Example

Complexity

See also