seek(n) Tcl Built-In Commands seek(n)

NAME
       seek - Change the access position for an open channel

SYNOPSIS
       sseeeekk channelId offset ?origin?



DESCRIPTION
       Changes the current access position for channelId.

       ChannelId must be an identifier for an open channel such as a Tcl stan- |
       dard channel (ssttddiinn, ssttddoouutt, or ssttddeerrrr), the return value from an invo- |
       cation  of  ooppeenn or ssoocckkeett, 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 origin must be one of the following:

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

       ccuurrrreenntt   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.

       eenndd       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 ssttaarrtt.

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

       Note that offset values are byte offsets, not character offsets.   Both |
       sseeeekk and tteellll operate in terms of bytes, not characters, unlike rreeaadd.


SEE ALSO
       file(n), open(n), close(n), gets(n), tell(n), TclStandardChannels(3)


KKEEYYWWOORRDDSS
       access position, file, seek



Tcl                                   8.1                              seek(n)