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std::basic_..._osyncstream(3)  C++ Standard Libary std::basic_..._osyncstream(3)

NAME
     std::basic_osyncstream::basic_osyncstream	 -   std::basic_osyncstream::ba-
     sic_osyncstream

Synopsis
	basic_osyncstream(  streambuf_type*   buf,   const   Allocator&   a   );
     (1)
	explicit       basic_osyncstream(	streambuf_type*      buf      );
     (2)
	basic_osyncstream( std::basic_ostream<CharT, Traits>& os, const  Alloca-
     tor& a ); (3)
	explicit  basic_osyncstream(  std::basic_ostream<CharT,  Traits>&  os );
     (4)
	basic_osyncstream(   std::basic_osyncstream&&	 other	  )    noexcept;
     (5)

	Constructs new synchronized output stream.

	1-4)  Constructs  the private member std::basic_syncbuf using the buffer
     and the
	allocator provided, and initializes the base class with a pointer to the
     member
	std::basic_streambuf.
	5) Move constructor. Move-constructs the std::basic_ostream base and the
	std::basic_syncbuf member from the corresponding  subobjects  of  other,
     then calls
	set_rdbuf  with the pointer to the newly-constructed underlying std::ba-
     sic_syncbuf to
	complete the initialization of the base. After this move constructor,
	other.get_wrapped() returns nullptr and destruction of other produces no
     output.

Parameters
	buf   - pointer to the std::basic_streambuf that will be wrapped
	os    - reference to a std::basic_ostream, whose rdbuf() will be wrapped
	a     - the allocator to pass to the constructor of the member	std::ba-
     sic_syncbuf
	other - another osyncstream to move from

Example
     // Run this code

      #include <iostream>
      #include <string_view>
      #include <syncstream>
      #include <thread>

      void worker(const int id, std::ostream &os)
      {
	  std::string_view block;
	  switch (id)
	  {
	      default: [[fallthrough]];
	      case 0: block = "aa";
		      break;
	      case 1: block = "aa";
		      break;
	      case 2: block = "aa";
		      break;
	      case 3: block = "aa";
		      break;
	  }
	  for (int i = 1; i <= 50; ++i)
	      os << block << std::flush;
	  os << std::endl;
      }

      int main()
      {
	  std::cout  << "Synchronized output should not cause any interference:"
     << std::endl;
	  {
	      auto scout1 = std::osyncstream{std::cout};
	      auto scout2 = std::osyncstream{std::cout};
	      auto scout3 = std::osyncstream{std::cout};
	      auto scout4 = std::osyncstream{std::cout};
	      auto w1 = std::jthread{worker, 0, std::ref(scout1)};
	      auto w2 = std::jthread{worker, 1, std::ref(scout2)};
	      auto w3 = std::jthread{worker, 2, std::ref(scout3)};
	      auto w4 = std::jthread{worker, 3, std::ref(scout4)};
	  }

	  std::cout << "\nLack of synchronization may cause some interference on
     output:"
		    << std::endl;
	  {
	      auto w1 = std::jthread{worker, 0, std::ref(std::cout)};
	      auto w2 = std::jthread{worker, 1, std::ref(std::cout)};
	      auto w3 = std::jthread{worker, 2, std::ref(std::cout)};
	      auto w4 = std::jthread{worker, 3, std::ref(std::cout)};
	  }
      }

Possible output:
      Synchronized output should not cause any interference:
      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

      Lack of synchronization may cause some interference on output:
      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
      aaaaaa

See also
		      constructs a basic_syncbuf object
	constructor	  (public     member	  function	of	std::ba-
     sic_syncbuf<CharT,Traits,Allocator>)

http://cppreference.com 	   2024.06.10	   std::basic_..._osyncstream(3)
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