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std::basic_...buf::seekoff(3) C++ Standard Libarystd::basic_...buf::seekoff(3)

NAME
       std::basic_spanbuf::seekoff - std::basic_spanbuf::seekoff

Synopsis
	  protected:

	  pos_type seekoff( off_type off, std::ios_base::seekdir dir,
			    std::ios_base::openmode	      which	     =
       (since C++23)

				std::ios_base::in | std::ios_base::out )
	  override;

	  Repositions the next pointer to get and/or put area, if possible, to
       the position
	  that corresponds to exactly off characters from beginning,  end,  or
       current position
	  of the get and/or put	area of	the buffer.

	  Let  n  be  the  number of CharT elements in underlying buffer, or 0
       when there is no
	  underlying buffer, this function fails if

	    * the next pointer to the get and/or put  area  to	reposition  is
       null and	the
	      computed	newoff	(see  below)  is  not zero, which may occur if
       there is	no
	      underlying buffer, or the	*this is not opened in	the  mode  re-
       quired by which,	or
	    *	dir  is	 std::ios_base::cur  and  both	std::ios_base::in  and
       std::ios_base::out are
	      set in which, or
	    * the computed newoff is not representable in off_type, less  than
       zero, or	greater
	      than n.

	  newoff is computed as	below:

	    * If dir is	std::ios_base::beg, newoff is off.
	    * If dir is	std::ios_base::cur, newoff is
		 *  pptr()  -  pbase()	+  off if std::ios_base::out is	set in
       which, or
		 * gptr() - eback() +  off  if	std::ios_base::in  is  set  in
       which.
	    * If dir is	std::ios_base::end, newoff is
		 *  pptr()  -  pbase()	+  off	if  std::ios_base::out but not
       std::ios_base::in is
		   set in the open mode	of *this,
		 * otherwise, off + n.

	  This function	repositions the	next pointer to	get and/or put area to
       pbuf + newoff
	  on success if	std::ios_base::in and/or std::ios_base::out is	corre-
       spondingly set in
	  which,  where	pbuf is	the pointer to the beginning of	the underlying
       buffer, or the
	  null pointer value if	there is no underlying buffer.

Parameters
	  off	- relative position to set the next pointer(s) to
		  defines base position	to apply the relative  offset  to.  It
       can be one of the
		  following constants:

	  dir	- Constant Explanation
		  beg	   the beginning of a stream
		  end	   the ending of a stream
		  cur	   the current position	of stream position indicator
		  defines whether the input sequences, the output sequence, or
       both are
		  affected.  It	 can  be one or	a combination of the following
       constants:
	  which	-
		  Constant Explanation
		  in	   affect the input sequence
		  out	   affect the output sequence

Return value
	  pos_type(newoff) on success, pos_type(off_type(-1)) on failure.

Example
	   This	section	is incomplete
	   Reason: no example

See also
		    repositions	the next pointer in the	input sequence,	output
       sequence, or
	  seekoff   both, using	relative addressing
	  [virtual] (virtual protected member function of
		    std::basic_stringbuf<CharT,Traits,Allocator>)
	  seekoff   repositions	the next pointer in the	input sequence,	output
       sequence, or
	  [virtual] both, using	relative addressing
		    (virtual protected member function of std::strstreambuf)

Category:
	    * Todo no example

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

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