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std::strstreambuf::setbuf(3)   C++ Standard Libary  std::strstreambuf::setbuf(3)

NAME
     std::strstreambuf::setbuf - std::strstreambuf::setbuf

Synopsis
	protected:						  (deprecated in
     C++98)
	virtual  streambuf*  setbuf(  char* s, std::streamsize n );  (removed in
     C++26)

	If s is a null pointer and n is zero, this function has no effect.

	Otherwise, the effect is implementation-defined: some implementations do
     nothing,
	while some implementations deallocate the dynamic member array	used  as
     the buffer
	and begin using the user-supplied character array of size n, whose first
     element is
	pointed to by s.

	This  function	is protected virtual, it may only be called through pub-
     setbuf() or
	from  member  functions   of   a   user-defined   class   derived   from
     std::strstreambuf.

Parameters
	s - pointer to the first byte in the user-provided buffer
	n - the number of bytes in the user-provided buffer

Return value
	this

Example
	Implementation	test  to  check  if  setbuf()  is supported on a dynamic
     strstream (output
	obtained with Sun Studio):

     // Run this code

      #include <iostream>
      #include <strstream>

      int main()
      {
	  char a[100] = {};
	  std::strstream str;
	  str.rdbuf()->pubsetbuf(a, sizeof a);
	  str << "Test string" << std::ends;
	  std::cout << "user-provided buffer holds \"" << a << "\"\n";
      }

Possible output:
      user-provided buffer holds "Test string"

	Defect reports

	The following behavior-changing defect	reports  were  applied	retroac-
     tively to
	previously published C++ standards.

	  DR   Applied to	     Behavior as published		 Correct
     behavior
			  the effect of setbuf() was "performs an
			  operation that is
	LWG 66 C++98	  defined separately for each class derived   the effect
     is
			  from	strstreambuf",			       implemen-
     tation-defined
			  but there are no classes derived from
			  strstreambuf

See also
	pubsetbuf invokes setbuf()
		  (public member function of std::basic_streambuf<CharT,Traits>)
	setbuf	  replaces the buffer with user-defined array, if permitted
	[virtual]  (virtual  protected	member	function  of  std::basic_stream-
     buf<CharT,Traits>)

	setbuf	   attempts to replace the controlled character sequence with an
     array
	[virtual] (virtual protected member function of
		  std::basic_stringbuf<CharT,Traits,Allocator>)
	setbuf	  provides user-supplied buffer or turns this filebuf unbuffered
	[virtual]  (virtual  protected	member	function   of	std::basic_file-
     buf<CharT,Traits>)

http://cppreference.com 	   2024.06.10	    std::strstreambuf::setbuf(3)
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