tell - Return current access position for an open channel
Returns an integer string giving the current access position in
channelId. This value returned is a byte offset that can be passed to
seek in order to set the channel to a particular position. Note
that this value is in terms of bytes, not characters like read.
The value returned is -1 for channels that do not support
access position, channel, seeking
Copyright © 1993 The Regents of the University of California.
Copyright © 1994-1996 Sun Microsystems, Inc.
Copyright © 1995-1997 Roger E. Critchlow Jr.