Set position of internal position pointer.
  This member is called to set a new value for the position pointer in a streambuf-derived object. Its default behavior for this class is just to return an invalid position.
  This is a virtual member function that should be redefined in derived classes to behave as expected setting a new position from an offset value (off) relative to a given direction (way) for the position pointers specified by parameter which.
  Standard class filebuf redefines this specifically for filebuf objects (filebuf::seekoff).

Parameters.

off

Offset value. This is relative to way parameter.
It is an integer value, an object of type streamoff.

way

It is an object of type ios_base::seekdir. It may take any of the following constant values:

• ios_base::beg (offset from the beginning of the stream's buffer).
• ios_base::cur (offset from the current position in the stream's buffer).
• ios_base::cur (offset from the end of the stream's buffer).

which

Determines which of the internal position pointers shall be modified, either in, out or both. It is an object of type ios_base::openmode that may take any combination of the following significant constant values:

• ios_base::in Modify input position.
• ios_base::out Modify output position.

Return Value.
  The new position value of the modified position pointer.
  In case of error the value returned is an invalid position.

Basic template member declaration ( basic_streambuf<charT,traits> ):

typedef traits::pos_type pos_type; typedef traits::off_type off_type; pos_type seekoff (off_type off, ios_base::seekdir way, ios_base which = ios_base::in | ios_base::out );

See also.
  pubseekoff, filebuf::seekoff
  streambuf class