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std::basic_ostream::seekp(3)   C++ Standard Libary  std::basic_ostream::seekp(3)

NAME
     std::basic_ostream::seekp - std::basic_ostream::seekp

Synopsis
	basic_ostream& seekp( pos_type pos );				  (1)
	basic_ostream& seekp( off_type off, std::ios_base::seekdir dir ); (2)

	Sets  the  output position indicator of the current associated streambuf
     object.

	Behaves   as   UnformattedOutputFunction   (except   without	actually
     (since C++11)
	performing output). After constructing and checking the sentry object,

	1)  if	fail()	!=  true, sets the output position indicator to absolute
     (relative to
	the beginning of the file) value pos by calling rdbuf()->pubseekpos(pos,
	std::ios_base::out).	In    case    of     failure,	  calls     set-
     state(std::ios_base::failbit).
	2)  if	fail() != true, sets the output position indicator to offset off
     relative to
	dir by calling	rdbuf()->pubseekoff(off,  dir,	std::ios_base::out).  In
     case of
	failure, calls setstate(std::ios_base::failbit).

Parameters
	pos - absolute position to set the output position indicator to
	off  -	relative position (positive or negative) to set the output posi-
     tion indicator
	      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

Return value
	*this

Exceptions
	1,2)  May  throw  std::ios_base::failure  in  case of failure, if excep-
     tions() & failbit
	!= 0.

Example
     // Run this code

      #include <iostream>
      #include <sstream>

      int main()
      {
	  std::ostringstream os("hello, world");
	  os.seekp(7);
	  os << 'W';
	  os.seekp(0, std::ios_base::end);
	  os << '!';
	  os.seekp(0);
	  os << 'H';
	  std::cout << os.str() << '\n';
      }

Output:
      Hello, World!

	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
	LWG 129  C++98	    there was no way to indicate a failure sets  failbit
     on failure
	LWG 136  C++98	    seekp could set the input stream	   only sets the
     output
								   stream
	LWG  537  C++98      1. the type of pos was pos_type&	    1. corrected
     to pos_type
			    2. the type of off was off_type&	   2.  corrected
     to off_type
	LWG 2341 C++98	    the resolution of LWG issue 129 for    restored
			    overload (2) was removed

See also
	tellp returns the output position indicator
	      (public member function)
	tellg returns the input position indicator
	      (public member function of std::basic_istream<CharT,Traits>)
	seekg sets the input position indicator
	      (public member function of std::basic_istream<CharT,Traits>)

http://cppreference.com 	   2024.06.10	    std::basic_ostream::seekp(3)
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