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std::basic_streambuf<CharT,Traits>::pubseekoff, std::basic_streambuf<CharT,Traits>::seekoff

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< cpp‎ | io‎ | basic streambuf
 
 
 
 
pos_type pubseekoff( off_type off, std::ios_base::seekdir dir,
                     std::ios_base::openmode which = ios_base::in | ios_base::out );
(1)
protected:

virtual pos_type seekoff( off_type off, std::ios_base::seekdir dir,

                          std::ios_base::openmode which = ios_base::in | ios_base::out );
(2)

Sets the position indicator of the input and/or output sequence relative to some other position.

1) Calls seekoff(off, dir, which) of the most derived class.
2) The base class version of this function has no effect. The derived classes may override this function to allow relative positioning of the position indicator.

Contents

[edit] Parameters

off - relative position to set the position indicator to.
dir - defines base position to apply the relative offset to. It can be one of the following constants:
Constant Explanation
beg the beginning of a stream
end the ending of a stream
cur the current position of stream position indicator
which - defines which of the input and/or output sequences to affect. It can be one or a combination of the following constants:
Constant Explanation
in affect the input sequence
out affect the output sequence

[edit] Note

Not all combinations of parameters may be valid, see the derived versions of seekoff for details.

[edit] Return value

1) The return value of seekoff(off, dir, which)
2) The resulting absolute position as defined by the position indicator. The base class version returns pos_type(off_type(-1)).

[edit] Example

[edit] Defect reports

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

DR Applied to Behavior as published Correct behavior
LWG 55 C++98 the base class version of seekoff returned
an undefined invalid stream position
returns pos_type(off_type(-1))

[edit] See also

invokes seekpos()
(public member function) [edit]
[virtual]
repositions the file position, using relative addressing
(virtual protected member function of std::basic_filebuf<CharT,Traits>) [edit]
[virtual]
repositions the next pointer in the input sequence, output sequence, or both, using relative addressing
(virtual protected member function of std::basic_stringbuf<CharT,Traits,Allocator>) [edit]
[virtual]
repositions the next pointer in the input sequence, output sequence, or both, using relative addressing
(virtual protected member function of std::strstreambuf) [edit]