fseek, ftell, rewind \- reposition a stream
.B fseek(stream, offset, ptrname)
sets the position of the next input or output
The new position is at the signed distance
from the beginning, the current position, or the end of the file,
has the value 0, 1, or 2.
returns the current value of the offset relative to the beginning
of the file associated with the named
It is measured in bytes on UNIX;
on some other systems it is a magic cookie,
and the only foolproof way to obtain an
.I "fseek(stream, 0L, 0)."
returns \-1 for improper seeks.