NAME
       seek - Change the access position for an open channel

SYNOPSIS
       seek channelId offset ?origin?


DESCRIPTION
       Changes the current access position for channelId.

       ChannelId  must  be an identifier for an open channel such
       as a Tcl standard channel (stdin, stdout, or stderr),  the
       return  value from an invocation of open or socket, or the
       result of a channel creation command  provided  by  a  Tcl
       extension.

       The  offset  and  origin arguments specify the position at
       which the next read or write  will  occur  for  channelId.
       Offset must be an integer (which may be negative) and ori-
       gin must be one of the following:

       start     The new access position  will  be  offset  bytes
                 from the start of the underlying file or device.

       current   The new access position  will  be  offset  bytes
                 from  the  current  access  position; a negative
                 offset moves the access  position  backwards  in
                 the underlying file or device.

       end       The  new  access  position  will be offset bytes
                 from the end of the file or device.  A  negative
                 offset places the access position before the end
                 of file, and a positive offset places the access
                 position after the end of file.

       The origin argument defaults to start.

       The  command  flushes  all buffered output for the channel
       before the command returns, even if the channel is in non-
       blocking  mode.   It also discards any buffered and unread
       input.  This command returns an empty  string.   An  error
       occurs if this command is applied to channels whose under-
       lying file or device does not support seeking.

       Note that offset values are byte  offsets,  not  character
       offsets.   Both  seek  and tell operate in terms of bytes,
       not characters, unlike read.


SEE ALSO
       file(n), open(n), close(n),  gets(n),  tell(n),  Tcl_Stan-
       dardChannels(3)


KEYWORDS
