tqt3/doc/y2k.doc

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** TQt Year 2000 Compliance
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/*! \page y2k.html

\title Year 2000 Compliance Statement

Trolltech defines <i>Year 2000 Compliance</i> as a requirement that a
product or part of product does not contain errors related to
transition from December 31, 1999 to January 1, 2000, or to the
existence of February 29, 2000.

This document certifies that the API provided by TQt and the
implementation of TQt are both Year 2000 Compliant, and that the use of
underlying APIs by TQt does not have any known problems.

\section1 The API Provided by Qt

Several parts of TQt deal with dates and times:
\list
\i \l QDate - provides date management
\i \l QDateTime - provides date/time management
\i \l QTime - provides time management (within a date)
\i \l QTimer - provides delayed or regular execution of code.
\endlist

All of these classes' external APIs are Year 2000 Compliant: QDate and
QDateTime offer only four-digit years as output, QTime and QTimer do
not deal with years or leap days at all.

\section1 Implementation Issues in Qt

All date/time calculation and storage in TQt uses number of days,
seconds or milliseconds, and is thus Year 2000 Compliant.

This applies to the above four classes and also to \l QFileDialog
(which can sort files by time/date), \l QFileInfo (which operates on
file times/dates) and \l QApplication (which does various internal
housekeeping tasks).

The conversion to <tt>year/month/date</tt> format in QDate (and
QDateTime) has been verified to be correct for all of December 31,
1999, January 1, 2000, February 28 and 29, 2000, March 1, 2000,
January 1, 2001 and March 1, 2001.

Qt has been verified to be robust in case of time/date errors (such as
time warps) in the underlying operating system.

\section1 Use of System APIs

It is of course impossible for Trolltech to ensure that both of the
window systems and all of the operating systems on which TQt runs are
Year 2000 Compliant. However, TQt does not use any APIs that are known
to have any Year 2000-related bugs, or seem at risk to have any.
*/