tell(3) [linux man page]

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

__________________________________________________________________________________________________________________________________________________

NAME

       tell - Return current access position for an open channel

SYNOPSIS

       tell channelId
_________________________________________________________________

DESCRIPTION

       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 seeking.

       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.

EXAMPLE

       Read a line from a file channel only if it starts with foobar:
              # Save the offset in case we need to undo the read...
              set offset [tell $chan]
              if {[read $chan 6] eq "foobar"} {
                  gets $chan line
              } else {
                  set line {}
                  # Undo the read...
                  seek $chan $offset
              }

SEE ALSO

       file(n), open(n), close(n), gets(n), seek(n), Tcl_StandardChannels(3)

KEYWORDS

       access position, channel, seeking

Tcl                                                                     8.1                                                                tell(n)

tell(1T)						       Tcl Built-In Commands							  tell(1T)

__________________________________________________________________________________________________________________________________________________

NAME

       tell - Return current access position for an open channel

SYNOPSIS

       tell channelId
_________________________________________________________________

DESCRIPTION

       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 seeking.

       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.

EXAMPLE

       Read a line from a file channel only if it starts with foobar:
	      # Save the offset in case we need to undo the read...
	      set offset [tell $chan]
	      if {[read $chan 6] eq "foobar"} {
		  gets $chan line
	      } else {
		  set line {}
		  # Undo the read...
		  seek $chan $offset
	      }

SEE ALSO

       file(1T), open(1T), close(1T), gets(1T), seek(1T), Tcl_StandardChannels(3TCL)

KEYWORDS

       access position, channel, seeking

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +--------------------+-----------------+
       |  ATTRIBUTE TYPE    | ATTRIBUTE VALUE |
       +--------------------+-----------------+
       |Availability	    | SUNWTcl	      |
       +--------------------+-----------------+
       |Interface Stability | Uncommitted     |
       +--------------------+-----------------+
NOTES

       Source for Tcl is available on http://opensolaris.org.

Tcl									8.1								  tell(1T)