GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages


Manual Reference Pages  -  TELL (n)

NAME

tell - Return current access position for an open channel

CONTENTS

Synopsis
Description
Example
Keywords

SYNOPSIS

tell channelId

   








\L’|0u-1v’\l’75u+3n_’\L’0u+1v-0u’\l’|0u-1.5n_’



\L’|0u-1v’\L’0u+1v-0u’\l’|0u-1.5n_’





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
Search for    or go to Top of page |  Section n |  Main Index


Tcl TELL (n) 8.1

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with manServer 1.07.