Set position of internal position pointer.
  Sets a new position from an offset value (off) relative to a given direction (way) for the position pointers specified by parameter which.

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 buffer).
• ios_base::cur (offset from the current position in the buffer).
• ios_base::end (offset from the end of the 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_stringbuf<charT,traits,Allocator> ):

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.
  streambuf::pubseekoff, seekpos
  stringbuf class