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

NAME
     std::memset - std::memset

Synopsis
	Defined in header <cstring>
	void* memset( void* dest, int ch, std::size_t count );

	Copies	the  value static_cast<unsigned char>(ch) into each of the first
     count
	characters of the object pointed to by dest. If the object is a
	potentially-overlapping subobject or  is  not  TriviallyCopyable  (e.g.,
     scalar,
	C-compatible struct, or an array of trivially copyable type), the behav-
     ior is
	undefined. If count is greater than the size of the object pointed to by
     dest, the
	behavior is undefined.

Parameters
	dest  - pointer to the object to fill
	ch    - fill byte
	count - number of bytes to fill

Return value
	dest

Notes
	std::memset  may be optimized away (under the as-if rules) if the object
     modified by
	this function is not accessed again for the rest of its lifetime  (e.g.,
     gcc bug
	8537).	For  that  reason,  this function cannot be used to scrub memory
     (e.g., to fill
	an array that stored a password with zeroes).

	Solutions for that include std::fill with volatile pointers, (C23)
	memset_explicit(), (C11) memset_s, FreeBSD explicit_bzero or Microsoft
	SecureZeroMemory.

Example
     // Run this code

      #include <bitset>
      #include <climits>
      #include <cstring>
      #include <iostream>

      int main()
      {
	  int a[4];
	  using bits = std::bitset<sizeof(int) * CHAR_BIT>;
	  std::memset(a, 0b1111'0000'0011, sizeof a);
	  for (int ai : a)
	      std::cout << bits(ai) << '\n';
      }

Output:
      00000011000000110000001100000011
      00000011000000110000001100000011
      00000011000000110000001100000011
      00000011000000110000001100000011

See also
	memcpy		      copies one buffer to another
			      (function)
	memmove 	      moves one buffer to another
			      (function)
			      copies the given wide character to every	position
     in a wide
	wmemset 	      character array
			      (function)
	fill		      copy-assigns the given value to every element in a
     range
			      (function template)
	fill_n		       copy-assigns  the  given value to N elements in a
     range
			      (function template)
	is_trivially_copyable checks if a type is trivially copyable
	(C++11) 	      (class template)
	C documentation for
	memset

http://cppreference.com 	   2024.06.10			  std::memset(3)
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