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std::uninitialized_fill(3)    C++ Standard Libary   std::uninitialized_fill(3)

NAME
       std::uninitialized_fill - std::uninitialized_fill

Synopsis
	  Defined in header <memory>
	  template< class ForwardIt, class T >
	  void	uninitialized_fill(  ForwardIt first, ForwardIt	last, const T&
       (1)
	  value	);
	  template< class ExecutionPolicy, class ForwardIt, class T >
	  void	 uninitialized_fill(   ExecutionPolicy&&   policy,   ForwardIt
       (2) (since C++17)
	  first, ForwardIt last, const T& value	);

	  1)  Copies  the given	value to an uninitialized memory area, defined
       by the range
	  [first, last)	as if by

	for (; first !=	last; ++first)
	    ::new (/*VOIDIFY*/(*first))
		typename std::iterator_traits<ForwardIt>::value_type(value);

	  where	/*VOIDIFY*/(e) is:

	     static_cast<void*>(&e)
       (until C++11)
	     static_cast<void*>(std::addressof(e))
       (since C++11)
										 (un-
       til C++20)
	     const_cast<void*>(static_cast<const		      volatile
       (since C++20)
	     void*>(std::addressof(e)))

	  If an	exception is thrown during the initialization, the objects al-
       ready 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>>
	  (until C++20)
	  std::is_execution_policy_v<std::remove_cvref_t<ExecutionPolicy>>
	  (since C++20)	is true.

Parameters
	  first, last	       -	 the range of the elements to initial-
       ize
	  value			-	   the value to	construct the elements
       with
	  policy	       -	 the execution policy to use. See exe-
       cution policy for
					 details.

Type requirements
	  -
	  ForwardIt must meet the requirements of LegacyForwardIterator.
	  -
	  No increment,	assignment, comparison,	or indirection	through	 valid
       instances of
	  ForwardIt may	throw exceptions.
	  Applying  &*	to a ForwardIt value must yield	a pointer to its value
       type.
	  (until C++11)

Return value
	  (none)

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::termi-
       nate 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 ForwardIt, class T>
	  void	uninitialized_fill(ForwardIt  first,  ForwardIt	last, const T&
       value)
	  {
	      using V =	typename std::iterator_traits<ForwardIt>::value_type;
	      ForwardIt	current	= first;
	      try {
		  for (; current != last; ++current) {
		      ::new   (const_cast<void*>(static_cast<const    volatile
       void*>(
			  std::addressof(*current)))) V(value);
		  }
	      }	 catch (...) {
		  for (; first != current; ++first) {
		      first->~V();
		  }
		  throw;
	      }
	  }

Example
       // Run this code

	#include <algorithm>
	#include <iostream>
	#include <memory>
	#include <string>
	#include <tuple>

	int main()
	{
	    std::string* p;
	    std::size_t	sz;
	    std::tie(p,	sz) = std::get_temporary_buffer<std::string>(4);

	    std::uninitialized_fill(p, p+sz, "Example");

	    for	(std::string* i	= p; i != p+sz;	++i) {
		std::cout << *i	<< '\n';
		i->~basic_string<char>();
	    }
	    std::return_temporary_buffer(p);
	}

Output:
Example
Example
Example
Example
See also
				     copies an object to an uninitialized area
       of memory,
	  uninitialized_fill_n	     defined by	a start	and a count
				     (function template)
	  ranges::uninitialized_fill copies an object to an uninitialized area
       of memory,
	  (C++20)		     defined by	a range
				     (niebloid)

http://cppreference.com		  2022.07.31	    std::uninitialized_fill(3)

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