# TIP 423: Formatting Timestamps with Milliseconds
	Author:		Thomas Perschak <tombert.group@live.at>
	State:		Draft
	Type:		Project
	Tcl-Version:	9.1
	Vote:		Pending
	Created:	07-Jun-2013
	Post-History:
	Keywords:	Tcl, time, millisecond resolution
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# Abstract

This TIP describes a change to **clock format** to allow it to handle
timestamps with sub-second accuracy.

# Rationale

Currently, the **clock format** accepts only integer numbers for clock
formatting. Since the **clock milliseconds** command was introduced in Tcl
8.5, this limitation seems a bit restrictive.

In particular, the timestamp column in a number of databases \(e.g.,
<http://www.postgresql.org/docs/9.1/static/datatype-datetime.html\)> handles
high-resolution timestamps by allowing full ISO 8601 times, which look like
"04:05:06.789"; this would simplify database write operations.

# Proposal

The **clock format** command should accept floating point values for
timestamps.

Another format letter should be added to **clock format** which puts the
milliseconds into the output string; the millisecond value should not be
written unless explicitly requested.

# Copyright

This document has been placed in the public domain.

