ntp_time (3)

NAME

ntp_time - Tcl Time Service Client

SYNOPSIS

package require Tcl 8.0

package require time ?1.2.1?

::time::gettime ?options? timeserver ?port?

::time::getsntp ?options? timeserver ?port?

::time::configure ?options?

::time::cget name

::time::unixtime token

::time::status token

::time::error token

::time::reset token ?reason?

::time::wait token

::time::cleanup token

DESCRIPTION

This package implements a client for the RFC 868 TIME protocol (www.rfc-editor.org/rfc/rfc868.txt) and also a minimal client for the RFC 2030 Simple Network Time Protocol (www.rfc-editor.org/rfc/rfc2030.txt). RFC 868 returns the time in seconds since 1 January 1900 to either tcp or udp clients. RFC 2030 also gives this time but also provides a fractional part which is not used in this client.

COMMANDS

::time::gettime ?options? timeserver ?port?

Get the time from timeserver. You may specify any of the options listed for the configure command here. This command returns a token which must then be used with the remaining commands in this package. Once you have finished, you should use cleanup to release all resources. The default port is 37.

::time::getsntp ?options? timeserver ?port?

Get the time from an SNTP server. This accepts exactly the same arguments as ::time::gettime except that the default port is 123. The result is a token as per ::time::gettime and should be handled in the same way.

Note that it is unlikely that any SNTP server will reply using tcp so you will require the tcludp or the ceptcl package. If a suitable package can be loaded then the udp protocol will be used by default.

::time::configure ?options?

Called with no arguments this command returns all the current configuration options and values. Otherwise it should be called with pairs of option name and value.

-protocol number

Set the default network protocol. This defaults to udp if the tcludp package is available. Otherwise it will use tcp.

-port number

Set the default port to use. RFC 868 uses port 37, RFC 2030 uses port 123.

-timeout number

Set the default timeout value in milliseconds. The default is 10 seconds.

-command number

Set a command procedure to be run when a reply is received. The procedure is called with the time token appended to the argument list.

-loglevel number

Set the logging level. The default is 'warning'.

::time::cget name

Get the current value for the named configuration option.

::time::unixtime token

Format the returned time for the unix epoch. RFC 868 time defines time 0 as 1 Jan 1900, while unix time defines time 0 as 1 Jan 1970. This command converts the reply to unix time.

::time::status token

Returns the status flag. For a successfully completed query this will be ok. May be error or timeout or eof. See also ::time::error

::time::error token

Returns the error message provided for requests whose status is error. If there is no error message then an empty string is returned.

::time::reset token ?reason?

Reset or cancel the query optionally specfying the reason to record for the error command.

::time::wait token

Wait for a query to complete and return the status upon completion.

::time::cleanup token

Remove all state variables associated with the request.

% set tok [::time::gettime ntp2a.mcc.ac.uk]
% set t [::time::unixtime $tok]
% ::time::cleanup $tok

% set tok [::time::getsntp pool.ntp.org]
% set t [::time::unixtime $tok]
% ::time::cleanup $tok

proc on_time {token} {
   if {[time::status $token] eq "ok"} {
      puts [clock format [time::unixtime $token]]
   } else {
      puts [time::error $token]
   }
   time::cleanup $token
}
time::getsntp -command on_time pool.ntp.org

AUTHORS

Pat Thoyts

BUGS, IDEAS, FEEDBACK

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category ntp of the Tcllib Trackers [core.tcl.tk/tcllib/reportlist] Please also report any ideas for enhancements you may have for either package and/or documentation.

SEE ALSO

ntp

KEYWORDS

NTP, SNTP, rfc 2030, rfc 868, time

CATEGORY

Networking

COPYRIGHT

Copyright (c) 2002, Pat Thoyts <patthoyts@users.sourceforge.net>