istream& seekg( streampos pos );
istream& seekg( streamoff off, ios::seek_dir dir );
pos
The new position value; streampos is a typedef equivalent to long.
off
The new offset value; streamoff is a typedef equivalent to long.
dir
The seek direction. Must be one of the following enumerators:
| Value | Meaning |
| ios::beg | Seek from the beginning of the stream. |
| ios::cur | Seek from the current position in the stream. |
| ios::end | Seek from the end of the stream. |
Changes the get pointer for the stream. Not all derived classes of istream need support positioning; it is most often used with file-based streams.