Provides date and time functions. More...

Public Methods
	QDateTime ()

	QDateTime (const QDate &date)

	QDateTime (const QDate &date, const QTime &time, const QTimeZone &timeZone)

	QDateTime (const QDate &date, const QTime &time, Qt::TimeSpec spec=Qt::LocalTime, int offsetSeconds=0)

	QDateTime (const QDateTime &other)

	QDateTime (QDateTime &&other)

	~QDateTime ()

QDateTime	addDays (qint64 days) const

QDateTime	addMonths (qint64 months) const

QDateTime	addMSecs (qint64 msecs) const

QDateTime	addSecs (qint64 secs) const

QDateTime	addYears (qint64 years) const

QDate	date () const

qint64	daysTo (const QDateTime &value) const

bool	isDaylightTime () const

bool	isNull () const

bool	isValid () const

qint64	msecsTo (const QDateTime &value) const

int	offsetFromUtc () const

bool	operator!= (const QDateTime &value) const

bool	operator< (const QDateTime &value) const

bool	operator<= (const QDateTime &value) const

QDateTime &	operator= (const QDateTime &other)

QDateTime &	operator= (QDateTime &&other)

bool	operator== (const QDateTime &value) const

bool	operator> (const QDateTime &value) const

bool	operator>= (const QDateTime &value) const

qint64	secsTo (const QDateTime &value) const

void	setDate (const QDate &date)

void	setMSecsSinceEpoch (qint64 msecs)

void	setOffsetFromUtc (int offsetSeconds)

void	setTime (const QTime &time)

void	setTime_t (quint64 seconds)

void	setTimeSpec (Qt::TimeSpec spec)

void	setTimeZone (const QTimeZone &toZone)

void	swap (QDateTime &other)

QTime	time () const

Qt::TimeSpec	timeSpec () const

QTimeZone	timeZone () const

QString	timeZoneAbbreviation () const

CFDateRef	toCFDate () const

QDateTime	toLocalTime () const

qint64	toMSecsSinceEpoch () const

NSDate *	toNSDate () const

QDateTime	toOffsetFromUtc (qint64 offsetSeconds) const

QString	toString (const QString &format) const

QString	toString (Qt::DateFormat format=Qt::TextDate) const

quint64	toTime_t () const

QDateTime	toTimeSpec (Qt::TimeSpec specification) const

QDateTime	toTimeZone (const QTimeZone &timeZone) const

QDateTime	toUTC () const

Static Public Methods
static QDateTime	currentDateTime ()

static QDateTime	currentDateTimeUtc ()

static qint64	currentMSecsSinceEpoch ()

static QDateTime	fromCFDate (CFDateRef date)

static QDateTime	fromMSecsSinceEpoch (qint64 msecs, const QTimeZone &timeZone)

static QDateTime	fromMSecsSinceEpoch (qint64 msecs, Qt::TimeSpec spec=Qt::LocalTime, int offsetFromUtc=0)

static QDateTime	fromNSDate (const NSDate *date)

static QDateTime	fromString (const QString &str, const QString &format)

static QDateTime	fromString (const QString &str, Qt::DateFormat format=Qt::TextDate)

static QDateTime	fromTime_t (quint64 seconds, const QTimeZone &timeZone)

static QDateTime	fromTime_t (quint64 seconds, Qt::TimeSpec spec=Qt::LocalTime, int offsetFromUtc=0)

Friends
QDataStream &	operator<< (QDataStream &stream, const QDateTime &dateTime)

QDataStream &	operator>> (QDataStream &stream, QDateTime &dateTime)

Detailed Description

The QDateTime class provides date and time functions.

A QDateTime object contains a calendar date and a clock time (a "datetime"). It is a combination of the QDate and QTime classes. It can read the current datetime from the system clock. It provides functions for comparing datetimes and for manipulating a datetime by adding a number of seconds, days, months, or years.

A QDateTime object is typically created either by giving a date and time explicitly in the constructor, or by using the static function currentDateTime() that returns a QDateTime object set to the system clock's time. The date and time can be changed with setDate() and setTime(). A datetime can also be set using the setTime_t() method which takes a POSIX-standard "number of seconds since 00:00:00 on January 1, 1970" value. The fromString() method returns a QDateTime, given a string and a date format used to interpret the date within the string.

The date() and time() methods provide access to the date and time parts of the datetime. The same information is provided in textual format by the toString() function.

QDateTime provides a full set of operators to compare two QDateTime objects where smaller means earlier and larger means later.

You can increment (or decrement) a datetime by a given number of milliseconds using addMSecs(), seconds using addSecs(), or days using addDays(). Similarly you can use addMonths() and addYears(). The daysTo() function returns the number of days between two datetimes, secsTo() returns the number of seconds between two datetimes, and msecsTo() returns the number of milliseconds between two datetimes.

QDateTime can store datetimes as local time or as UTC. QDateTime::currentDateTime() returns a QDateTime expressed as local time, use toUTC() to convert it to UTC. You can also use timeSpec() to find out if a QDateTime object stores a UTC time or a local time. Operations such as addSecs() and secsTo() are aware of daylight saving time (DST).

Note: QDateTime does not account for leap seconds.

Gregorian and Julian Calendars

QDate uses the Gregorian calendar in all locales, beginning on the date 15 October 1582. For dates up to and including 4 October 1582, the Julian calendar is used. This means there is a 10-day gap in the internal calendar between the 4th and the 15th of October 1582. When you use QDateTime for dates in that epoch, the day after 4 October 1582 is 15 October 1582, and the dates in the gap are invalid.

The Julian to Gregorian changeover date used here is the date when the Gregorian calendar was first introduced, by Pope Gregory XIII. That change was not universally accepted and some localities only executed it at a later date (if at all). QDateTime does not take any of these historical facts into account. If an application must support a locale-specific dating system, it must do so on its own, remembering to convert the dates using the Julian day.

No Year 0

There is no year 0. Dates in that year are considered invalid. The year -1 is the year "1 before Christ" or "1 before current era". The day before 0001-01-01 is December 31st, 1 BCE.

Range of Valid Dates

The range of valid values able to be stored in QDateTime is dependent on the internal storage implementation. QDateTime is currently stored in a qint64 as a serial msecs value encoding the date and time. This restricts the date range to about +/- 292 million years, compared to the QDate range of +/- 2 billion years. Care must be taken when creating a QDateTime with extreme values that you do not overflow the storage. The exact range of supported values varies depending on the Qt::TimeSpec and time zone.

Use of System Timezone

QDateTime uses the system's time zone information to determine the offset of local time from UTC. If the system is not configured correctly or not up-to-date, QDateTime will give wrong results as well.

Daylight Saving Time (DST)

QDateTime takes into account the system's time zone information when dealing with DST. On modern Unix systems, this means it applies the correct historical DST data whenever possible. On Windows, where the system does not support historical DST data, historical accuracy is not maintained with respect to DST.

The range of valid dates taking DST into account is 1970-01-01 to the present, and rules are in place for handling DST correctly until 2037-12-31, but these could change. For dates falling outside that range, QDateTime makes a best guess using the rules for year 1970 or 2037, but we can not guarantee accuracy. This means QDateTime does not take into account changes in a locale's time zone before 1970, even if the system's time zone database supports that information.

QDateTime takes into consideration the Standard Time to Daylight-Saving Time transition. For example if the transition is at 2am and the clock goes forward to 3am, then there is a "missing" hour from 02:00:00 to 02:59:59.999 which QDateTime considers to be invalid. Any date maths performed will take this missing hour into account and return a valid result.

Offset From UTC

A Qt::TimeSpec of Qt::OffsetFromUTC is also supported. This allows you to define a QDateTime relative to UTC at a fixed offset of a given number of seconds from UTC. For example, an offset of +3600 seconds is one hour ahead of UTC and is usually written in ISO standard notation as "UTC+01:00". Daylight-Saving Time never applies with this TimeSpec.

There is no explicit size restriction to the offset seconds, but there is an implicit limit imposed when using the toString() and fromString() methods which use a format of [+|-]hh:mm, effectively limiting the range to +/- 99 hours and 59 minutes and whole minutes only. Currently no time zone lies outside the range of +/- 14 hours.

Time Zone Support

A Qt::TimeSpec of Qt::TimeZone is also supported in conjunction with the QTimeZone class. This allows you to define a datetime in a named time zone adhering to a consistent set of daylight-saving transition rules. For example a time zone of "Europe/Berlin" will apply the daylight-saving rules as used in Germany since 1970. The transition rules applied depend on the supported platform.

See also: QDate, QTime, QDateTimeEdit, QTimeZone

Constructor & Destructor Documentation

QDateTime::QDateTime ( )

Constructs a null date and null time. A null datetime is invalid since the date is invalid.

See also: isValid()

QDateTime::QDateTime ( const QDate & date )

explicit

Constructs a QDateTime with the given date and a valid time of 00:00:00.000. Sets the timeSpec() to Qt::LocalTime.

QDateTime::QDateTime	(	const QDate &	date,
		const QTime &	time,
		Qt::TimeSpec	spec = `Qt::LocalTime`,
		int	offsetSeconds = `0`
	)

Constructs a datetime with the given date and time using the time specification defined by spec and offsetSeconds seconds.

If date is valid and time is not, the time will be set to midnight.

If the spec is not Qt::OffsetFromUTC then offsetSeconds will be ignored.

If the spec is Qt::OffsetFromUTC and offsetSeconds is 0 then the timeSpec() will be set to Qt::UTC, which is an offset of 0 seconds.

If spec is Qt::TimeZone then the spec will be set to Qt::LocaleTime which is the current system time zone.

To create a QDateTime with a Qt::TimeZone, a different constructor must be used.

QDateTime::QDateTime	(	const QDate &	date,
		const QTime &	time,
		const QTimeZone &	timeZone
	)

Constructs a datetime with the given date and time using the Time Zone specified by timeZone. If date is valid and time is not the time will be set to midnight. If timeZone is invalid than the datetime will be invalid.

QDateTime::QDateTime ( const QDateTime & other )

Copy constructs a new QDateTime from other.

QDateTime::QDateTime ( QDateTime && other )

Move constructs a new QDateTime from other.

QDateTime::~QDateTime ( )

Destroys the datetime.

Method Documentation

QDateTime QDateTime::addDays ( qint64 days ) const

nodiscard

Returns a QDateTime object containing the number of days later than the datetime of this object, or earlier if days is negative.

See also: daysTo(), addMonths(), addYears(), addSecs()

QDateTime QDateTime::addMonths ( qint64 months ) const

nodiscard

Returns a QDateTime object containing a datetime months later than the datetime of this object, or earlier if months is negative.

See also: daysTo(), addDays(), addYears(), addSecs()

QDateTime QDateTime::addMSecs ( qint64 msecs ) const

nodiscard

Returns a QDateTime object containing a datetime msecs milliseconds later than the datetime of this object (or earlier if msecs is negative).

See also: addSecs(), msecsTo(), addDays(), addMonths(), addYears()

QDateTime QDateTime::addSecs ( qint64 secs ) const

nodiscard

Returns a QDateTime object containing a datetime secs seconds later than the datetime of this object, or earlier if secs is negative.

See also: addMSecs(), secsTo(), addDays(), addMonths(), addYears()

QDateTime QDateTime::addYears ( qint64 years ) const

nodiscard

Returns a QDateTime object containing a datetime years later than the datetime of this object, or earlier if years is negative.

See also: daysTo(), addDays(), addMonths(), addSecs()

QDateTime QDateTime::currentDateTime ( )

static

Returns the current datetime, as reported by the system clock, in the local time zone.

See also: currentDateTimeUtc(), QDate::currentDate(), QTime::currentTime(), toTimeSpec()

QDateTime QDateTime::currentDateTimeUtc ( )

static

Returns the current datetime, as reported by the system clock, in UTC.

See also: currentDateTime(), QDate::currentDate(), QTime::currentTime(), toTimeSpec()

qint64 QDateTime::currentMSecsSinceEpoch ( )

static

Returns the number of milliseconds since 1970-01-01T00:00:00 Universal Coordinated Time. This number is like the POSIX time_t variable, but expressed in milliseconds instead.

See also: currentDateTime(), currentDateTimeUtc(), toTime_t(), toTimeSpec()

QDate QDateTime::date ( ) const

Returns the date part of the datetime.

See also: setDate(), time(), timeSpec()

qint64 QDateTime::daysTo ( const QDateTime & value ) const

Returns the number of days from this datetime to the value datetime. If the other datetime is earlier than this datetime, the value returned is negative.

See also: addDays(), secsTo(), msecsTo()

QDateTime QDateTime::fromCFDate ( CFDateRef date )

static

Constructs a new QDateTime containing a copy of the CFDate date.

See also: toCFDate()

QDateTime QDateTime::fromMSecsSinceEpoch	(	qint64	msecs,
		const QTimeZone &	timeZone
	)

static

Returns a datetime whose date and time are the number of milliseconds, msecs, that have passed since 1970-01-01T00:00:00.000, Coordinated Universal Time (Qt::UTC) and with the given timeZone.

See also: fromTime_t()

QDateTime QDateTime::fromMSecsSinceEpoch	(	qint64	msecs,
		Qt::TimeSpec	spec = `Qt::LocalTime`,
		int	offsetFromUtc = `0`
	)

static

Returns a datetime whose date and time are the number of milliseconds msecs that have passed since 1970-01-01T00:00:00.000, Coordinated Universal Time (Qt::UTC) and converted to the given spec.

If the spec is not Qt::OffsetFromUTC then the offsetFromUtc will be ignored. If the spec is Qt::OffsetFromUTC and the offsetSeconds is 0 then the spec will be set to Qt::UTC, i.e. an offset of 0 seconds.

See also: fromTime_t()

QDateTime QDateTime::fromNSDate ( const NSDate * date )

static

Constructs a new QDateTime containing a copy of the NSDate date.

See also: toNSDate()

QDateTime QDateTime::fromString	(	const QString &	str,
		const QString &	format
	)

static

Returns the QDateTime represented by the str, using the format given, or an invalid datetime if the string can not be parsed.

These expressions may be used for the date part of the format string.

Expression	Output
d	the day as number without a leading zero (1 to 31)
dd	the day as number with a leading zero (01 to 31)
ddd	the abbreviated localized day name (e.g. 'Mon' to 'Sun'). Uses QDate::shortDayName().
dddd	the long localized day name (e.g. 'Monday' to 'Sunday'). Uses QDate::longDayName().
M	the month as number without a leading zero (1-12)
MM	the month as number with a leading zero (01-12)
MMM	the abbreviated localized month name (e.g. 'Jan' to 'Dec'). Uses QDate::shortMonthName().
MMMM	the long localized month name (e.g. 'January' to 'December'). Uses QDate::longMonthName().
yy	the year as two digit number (00-99)
yyyy	the year as four digit number

Note: Unlike the other version of this function, day and month names must be given in the user's local language. It is only possible to use the English names if the user's language is English.

These expressions may be used for the time part of the format string.

Expression	Output
h	hour without a leading zero (0 to 23 or 1 to 12 if AM/PM display)
hh	hour with a leading zero (00 to 23 or 01 to 12 if AM/PM display)
H	hour without a leading zero (0 to 23, even with AM/PM display)
HH	hour with a leading zero (00 to 23, even with AM/PM display)
m	minute without a leading zero (0 to 59)
mm	minute with a leading zero (00 to 59)
s	second without a leading zero (0 to 59)
ss	second with a leading zero (00 to 59)
z	milliseconds without leading zeroes (0 to 999)
zzz	milliseconds with leading zeroes (000 to 999)
AP or A	interpret as an AM/PM time, AP must be either "AM" or "PM".
ap or a	Interpret as an AM/PM time, ap must be either "am" or "pm".

All other input characters will be treated as text. Any sequence of characters that are enclosed in singlequotes will also be treated as text and not be used as an expression.

QTime time1 = QTime::fromString("131", "HHh");
// time1 is 13:00:00
 
QTime time2 = QTime::fromString("1apA", "1amAM");
// time2 is 01:00:00
 
QDateTime dateTime = QDateTime::fromString("M1d1y9800:01:02", "'M'M'd'd'y'yyhh:mm:ss");
// dateTime is 1 January 1998 00:01:02

If the format is not satisfied an invalid QDateTime is returned. The expressions that do not have leading zeroes (d, M, h, m, s, z) will be greedy. This means that they will use two digits even if this will put them outside the range and/or leave too few digits for other sections.

QDateTime dateTime = QDateTime::fromString("130", "Mm"); // invalid

This could have meant 1 January 00:30.00 but the M will grab two digits.

For any field that is not represented in the format the following defaults are used:

Field	Default value
Year	1900
Month	1 (January)
Day	1
Hour	0
Minute	0
Second	0

QDateTime dateTime = QDateTime::fromString("1.30.1", "M.d.s");

// dateTime is January 30 in 1900 at 00:00:01.

See also: QDate::fromString(), QTime::fromString(), QDate::toString()

QDateTime QDateTime::fromString	(	const QString &	str,
		Qt::DateFormat	format = `Qt::TextDate`
	)

static

Returns the QDateTime represented by the str, using the format given, or an invalid datetime if this is not possible.

For Qt::TextDate it is recommended you use the English short month names (for example, "Jan"). Although localized month names can also be used, they depend on the user's locale settings.

QDateTime QDateTime::fromTime_t	(	quint64	seconds,
		const QTimeZone &	timeZone
	)

static

Returns a datetime whose date and time are the number of seconds that have passed since 1970-01-01T00:00:00, Coordinated Universal Time (Qt::UTC) and with the given timeZone.

See also: toTime_t(), setTime_t()

QDateTime QDateTime::fromTime_t	(	quint64	seconds,
		Qt::TimeSpec	spec = `Qt::LocalTime`,
		int	offsetFromUtc = `0`
	)

static

Returns a datetime whose date and time are the number of seconds that have passed since 1970-01-01T00:00:00, Coordinated Universal Time (Qt::UTC) and converted to the given spec.

If the spec is not Qt::OffsetFromUTC then the offsetSeconds will be ignored. If the spec is Qt::OffsetFromUTC and the offsetSeconds is 0 then the spec will be set to Qt::UTC, which is an offset of 0 seconds.

See also: toTime_t(), setTime_t()

bool QDateTime::isDaylightTime ( ) const

Returns if this datetime falls in Daylight-Saving Time. If the Qt::TimeSpec is not Qt::LocalTime or Qt::TimeZone then will always return false.

See also: timeSpec()

bool QDateTime::isNull ( ) const

Returns true if both the date and the time are null, otherwise returns false. A null datetime is invalid.

See also: QDate::isNull(), QTime::isNull(), isValid()

bool QDateTime::isValid ( ) const

Returns true if both the date and the time are valid, otherwise returns false.

See also: QDate::isValid(), QTime::isValid()

qint64 QDateTime::msecsTo ( const QDateTime & value ) const

Returns the number of milliseconds from this datetime to the value datetime. If the other datetime is earlier than this datetime, the value returned is negative.

Before performing the comparison, the two datetimes are converted to Qt::UTC to ensure that the result is correct if one of the two datetimes has daylight saving time (DST) and the other does not.

See also: addMSecs(), daysTo(), QTime::msecsTo()

int QDateTime::offsetFromUtc ( ) const

Returns the current Offset From UTC in seconds. If the timeSpec() is Qt::OffsetFromUTC this will be the value originally set.

If the timeSpec() is Qt::LocalTime this will be the difference between the Local Time and UTC including any Daylight Saving Offset.

If the timeSpec() is Qt::UTC this will be 0.

See also: setOffsetFromUtc()

bool QDateTime::operator!= ( const QDateTime & value ) const

inline

Returns true if this datetime is different from the value datetime, otherwise returns false.

Two datetimes are different if either the date, the time, or the time zone components are different.

See also: operator==()

bool QDateTime::operator< ( const QDateTime & value ) const

Returns true if this datetime is earlier than the value datetime, otherwise returns false.

bool QDateTime::operator<= ( const QDateTime & value ) const

inline

Returns true if this datetime is earlier than or equal to the value datetime, otherwise returns false.

QDateTime & QDateTime::operator= ( const QDateTime & other )

Copy assigns from other and returns a reference to this object.

QDateTime & QDateTime::operator= ( QDateTime && other )

inline

Move assigns from other and returns a reference to this object.

bool QDateTime::operator== ( const QDateTime & value ) const

Returns true if this datetime is equal to the value datetime, otherwise returns false.

See also: operator!=()

bool QDateTime::operator> ( const QDateTime & value ) const

inline

Returns true if this datetime is later than the value datetime, otherwise returns false.

bool QDateTime::operator>= ( const QDateTime & value ) const

inline

Returns true if this datetime is later than or equal to the value datetime, otherwise returns false.

qint64 QDateTime::secsTo ( const QDateTime & value ) const

Returns the number of seconds from this datetime to the value datetime. If the other datetime is earlier than this datetime, the value returned is negative.

Before performing the comparison, the two datetimes are converted to Qt::UTC to ensure that the result is correct if one of the two datetimes has daylight saving time (DST) and the other does not.

QDateTime now = QDateTime::currentDateTime();
QDateTime xmas(QDate(now.date().year(), 12, 25), QTime(0, 0));
 
qDebug("There are %d seconds to Christmas", now.secsTo(xmas));

See also: addSecs(), daysTo(), QTime::secsTo()

void QDateTime::setDate ( const QDate & date )

Sets the date part of this datetime to date. If no time is set, it is set to midnight.

See also: date(), setTime(), setTimeSpec()

void QDateTime::setMSecsSinceEpoch ( qint64 msecs )

Sets the date and time given the number of milliseconds, msecs, that have passed since 1970-01-01T00:00:00.000, Coordinated Universal Time (Qt::UTC). On systems that do not support time zones this function will behave as if local time were Qt::UTC.

There are possible values for msecs that lie outside the valid range of QDateTime, both negative and positive. The behavior of this method is undefined for those values.

See also: toMSecsSinceEpoch(), setTime_t()

void QDateTime::setOffsetFromUtc ( int offsetSeconds )

Sets the timeSpec() to Qt::OffsetFromUTC and the offset to offsetSeconds. The datetime will refer to a different point in time.

The maximum and minimum offset is 14 positive or negative hours. If offsetSeconds is larger or smaller than that, then the result is undefined. If offsetSeconds is 0 then the timeSpec() will be set to Qt::UTC.

See also: isValid(), offsetFromUtc()

void QDateTime::setTime ( const QTime & time )

Sets the time part of this datetime to time.

See also: time(), setDate(), setTimeSpec()

void QDateTime::setTime_t ( quint64 seconds )

Sets the date and time given the number of seconds that have passed since 1970-01-01T00:00:00, Coordinated Universal Time (Qt::UTC). On systems that do not support time zones this function will behave as if local time were Qt::UTC.

See also: toTime_t()

void QDateTime::setTimeSpec ( Qt::TimeSpec spec )

Sets the time specification used in this datetime to spec.

See also: timeSpec(), setDate(), setTime(), Qt::TimeSpec

void QDateTime::setTimeZone ( const QTimeZone & toZone )

Sets the time zone used in this datetime to toZone. The datetime will refer to a different point in time. If toZone is invalid then the datetime will be invalid.

See also: timeZone(), Qt::TimeSpec

void QDateTime::swap ( QDateTime & other )

inline

Swaps other with this object. This operation is very fast and never fails.

QTime QDateTime::time ( ) const

Returns the time part of the datetime.

See also: setTime(), date(), timeSpec()

Qt::TimeSpec QDateTime::timeSpec ( ) const

Returns the time specification of the datetime.

See also: setTimeSpec(), date(), time(), Qt::TimeSpec

QTimeZone QDateTime::timeZone ( ) const

Returns the time zone of the datetime.

If the timeSpec() is Qt::LocalTime then an instance of the current system time zone will be returned. Note however that if you copy this time zone the instance will not remain in sync if the system time zone changes.

See also: setTimeZone(), Qt::TimeSpec

QString QDateTime::timeZoneAbbreviation ( ) const

Returns the Time Zone Abbreviation for the datetime.

If the timeSpec() is Qt::UTC this will be "UTC". If the timeSpec() is Qt::OffsetFromUTC and the offset is not zero, this will be in the format "UTC[+-]00:00". If the timeSpec() is Qt::LocalTime then the host system is queried for the correct abbreviation.

Abbreviations may or may not be localized and they are not guaranteed to be a unique value. For example, different time zones may have the same abbreviation.

See also: timeSpec(), Qt::TimeSpec

CFDateRef QDateTime::toCFDate ( ) const

Creates a CFDate from a QDateTime. The caller owns the CFDate object and is responsible for releasing it.

See also: fromCFDate()

QDateTime QDateTime::toLocalTime ( ) const

inline

Returns a datetime containing the date and time information in this datetime, but specified using the Qt::LocalTime definition.

See also: toTimeSpec()

qint64 QDateTime::toMSecsSinceEpoch ( ) const

Returns the datetime as the number of milliseconds that have passed since 1970-01-01T00:00:00.000, Coordinated Universal Time (Qt::UTC). On systems that do not support time zones, this function will behave as if local time were Qt::UTC.

The behavior for this function is undefined if the datetime stored in this object is not valid. However, for all valid dates, this function returns a unique value.

See also: toTime_t(), setMSecsSinceEpoch()

NSDate * QDateTime::toNSDate ( ) const

Creates an NSDate from a QDateTime. The NSDate object is autoreleased.

See also: fromNSDate()

QDateTime QDateTime::toOffsetFromUtc ( qint64 offsetSeconds ) const

Returns a copy of this datetime converted to a spec of Qt::OffsetFromUTC with the given offsetSeconds. If the offsetSeconds equals 0 then a UTC datetime will be returned.

See also: setOffsetFromUtc(), offsetFromUtc(), toTimeSpec()

QString QDateTime::toString ( const QString & format ) const

Returns the datetime as a string. The format parameter determines the format of the result string.

These expressions may be used for the date:

Expression	Output
d	the day as number without a leading zero (1 to 31)
dd	the day as number with a leading zero (01 to 31)
ddd	the abbreviated localized day name (e.g. 'Mon' to 'Sun'). Uses QDate::shortDayName().
dddd	the long localized day name (e.g. 'Monday' to 'Sunday'). Uses QDate::longDayName().
M	the month as number without a leading zero (1-12)
MM	the month as number with a leading zero (01-12)
MMM	the abbreviated localized month name (e.g. 'Jan' to 'Dec'). Uses QDate::shortMonthName().
MMMM	the long localized month name (e.g. 'January' to 'December'). Uses QDate::longMonthName().
yy	the year as two digit number (00-99)
yyyy	the year as four digit number

These expressions may be used for the time:

Expression	Output
h	hour without a leading zero (0 to 23 or 1 to 12 if AM/PM display)
hh	hour with a leading zero (00 to 23 or 01 to 12 if AM/PM display)
m	minute without a leading zero (0 to 59)
mm	minute with a leading zero (00 to 59)
s	second without a leading zero (0 to 59)
ss	second with a leading zero (00 to 59)
z	milliseconds without leading zeroes (0 to 999)
zzz	milliseconds with leading zeroes (000 to 999)
AP	AM/PM display. AP will be replaced by either "AM" or "PM".
ap	am/pm display. ap will be replaced by either "am" or "pm".

All other input characters will be ignored. Any sequence of characters that are enclosed in singlequotes will be treated as text and not be used as an expression. Two consecutive singlequotes ("''") are replaced by a singlequote in the output.

Example format strings (assumed that the QDateTime is 21 May 2001 14:13:09):

Format	Result
dd.MM.yyyy	21.05.2001
ddd MMMM d yy	Tue May 21 01
hh:mm:ss.zzz	14:13:09.042
h:m:s ap	2:13:9 pm

If the datetime is invalid, an empty string will be returned.

See also: QDate::toString(), QTime::toString()

QString QDateTime::toString ( Qt::DateFormat format = Qt::TextDate ) const

Returns the datetime as a string in the format given.

If the format is Qt::TextDate, the string is formatted in the default way. QDate::shortDayName(), QDate::shortMonthName(), and QTime::toString() are used to generate the string, so the day and month names will be localized names. An example of this formatting is "Wed March 14 03:40:13 2011".

If the format is Qt::ISODate the string format corresponds to the ISO 8601 extended specification for representations of dates and times. It will use the form YYYY-MM-DDTHH:mm:ss[Z|[+|-]HH:mm], depending on the timeSpec() of the QDateTime. If the timeSpec() is Qt::UTC, Z will be appended to the string. If the timeSpec() is Qt::OffsetFromUTC the offset in hours and minutes from UTC will be appended to the string.

If the format is Qt::SystemLocaleShortDate or Qt::SystemLocaleLongDate, the string format depends on the locale settings of the system. Identical to calling QLocale::system().toString(datetime, QLocale::ShortFormat) or QLocale::system().toString(datetime, QLocale::LongFormat).

If the format is Qt::DefaultLocaleShortDate or Qt::DefaultLocaleLongDate, the string format depends on the default application locale. This is the locale set with QLocale::setDefault(), or the system locale if no default locale has been set. Identical to calling QLocale().toString(datetime, QLocale::ShortFormat) or QLocale().toString(datetime, QLocale::LongFormat).

If the datetime is invalid an empty string will be returned.

Warning: The Qt::ISODate format is only valid for years in the range 0 to 9999. This restriction may apply to locale-aware formats as well, depending on the locale settings.

See also: QDate::toString(), QTime::toString(), Qt::DateFormat

quint64 QDateTime::toTime_t ( ) const

Returns the datetime as the number of seconds that have passed since 1970-01-01T00:00:00, Coordinated Universal Time (Qt::UTC).

On systems that do not support time zones, this function will behave as if local time were Qt::UTC.

Note: This function returns a 32-bit unsigned integer, so it does not support dates before 1970, but it does support dates after 2038-01-19T03:14:06, which may not be valid time_t values. Be careful when passing those time_t values to system functions, which could interpret them as negative dates.

If the date is outside the range 1970-01-01T00:00:00 to 2106-02-07T06:28:14, this function returns -1 cast to an unsigned integer (i.e., 0xFFFFFFFF).

To get an extended range use toMSecsSinceEpoch().

See also: toMSecsSinceEpoch(), setTime_t()

QDateTime QDateTime::toTimeSpec ( Qt::TimeSpec specification ) const

Returns a copy of this datetime configured to use the given time specification.

See also: timeSpec(), toUTC(), toLocalTime()

QDateTime QDateTime::toTimeZone ( const QTimeZone & timeZone ) const

Returns a copy of this datetime converted to the given timeZone.

See also: timeZone(), toTimeSpec()

QDateTime QDateTime::toUTC ( ) const

inline

Returns a datetime containing the date and time information in this datetime, but specified using the Qt::UTC definition.

See also: toTimeSpec()

Friends And Related Function Documentation

QDataStream & operator<<	(	QDataStream &	stream,
		const QDateTime &	dateTime
	)

friend

Writes the given dateTime to the stream. Returns a reference to the stream.

Refer to Serializing Data Types for additional information.

QDataStream & operator>>	(	QDataStream &	stream,
		QDateTime &	dateTime
	)

friend

Reads from the stream into the given dateTime. Returns a reference to the stream.

Refer to Serializing Data Types for additional information.

Public Methods

Static Public Methods

Friends

Detailed Description

Gregorian and Julian Calendars

No Year 0

Range of Valid Dates

Use of System Timezone

Daylight Saving Time (DST)

Offset From UTC

Time Zone Support

Constructor & Destructor Documentation

Method Documentation

Friends And Related Function Documentation