\inmodule QtCore \reentrant More...

#include <qdatetime.h>

Collaboration diagram for QDate:

Public Types
using	difference_type = qint64

Public Member Functions
constexpr	QDate ()
	Constructs a null date.
	QDate (int y, int m, int d)
	Constructs a date with year y, month m and day d.
	QDate (int y, int m, int d, QCalendar cal)
constexpr bool	isNull () const
	Returns `true` if the date is null; otherwise returns `false`.
constexpr bool	isValid () const
	Returns `true` if this date is valid; otherwise returns `false`.
int	year () const
int	month () const
int	day () const
int	dayOfWeek () const
int	dayOfYear () const
int	daysInMonth () const
int	daysInYear () const
int	weekNumber (int *yearNum=nullptr) const
	Returns the ISO 8601 week number (1 to 53).
int	year (QCalendar cal) const
int	month (QCalendar cal) const
int	day (QCalendar cal) const
int	dayOfWeek (QCalendar cal) const
int	dayOfYear (QCalendar cal) const
int	daysInMonth (QCalendar cal) const
int	daysInYear (QCalendar cal) const
QDateTime	startOfDay (const QTimeZone &zone) const
QDateTime	endOfDay (const QTimeZone &zone) const
QDateTime	startOfDay () const
QDateTime	endOfDay () const
bool	setDate (int year, int month, int day)
bool	setDate (int year, int month, int day, QCalendar cal)
void	getDate (int year, int month, int *day) const
QDate	addDays (qint64 days) const
	Returns a QDate object containing a date ndays later than the date of this object (or earlier if ndays is negative).
QDate	addMonths (int months) const
QDate	addYears (int years) const
QDate	addMonths (int months, QCalendar cal) const
QDate	addYears (int years, QCalendar cal) const
qint64	daysTo (QDate d) const
	Returns the number of days from this date to d (which is negative if d is earlier than this date).
constexpr qint64	toJulianDay () const
	Converts the date to a Julian day.

Static Public Member Functions
static QDate	currentDate ()
	Returns the system clock's current date.
static bool	isValid (int y, int m, int d)
static bool	isLeapYear (int year)
	Returns `true` if the specified year is a leap year in the Gregorian calendar; otherwise returns `false`.
static constexpr QDate	fromJulianDay (qint64 jd_)
	Converts the Julian day jd to a QDate.

Friends
class	QDateTime
class	QDateTimeParser
class	QDateTimePrivate
constexpr bool	comparesEqual (const QDate &lhs, const QDate &rhs) noexcept
constexpr Qt::strong_ordering	compareThreeWay (const QDate &lhs, const QDate &rhs) noexcept
QDate &	operator++ (QDate &date) noexcept
QDate &	operator-- (QDate &date) noexcept
QDate	operator++ (QDate &date, int) noexcept
QDate	operator-- (QDate &date, int) noexcept
Q_CORE_EXPORT QDataStream &	operator<< (QDataStream &, QDate)
	Writes the date to stream out.
Q_CORE_EXPORT QDataStream &	operator>> (QDataStream &, QDate &)
	Reads a date from stream in into the date.

Related Symbols
(Note that these are not member symbols.)
	dayOfYear
	startOfDay
	endOfDay
	dayOfYear
	startOfDay
	endOfDay

Detailed Description

\inmodule QtCore \reentrant

The QDate class provides date functions.

\compares strong \compareswith strong std::chrono::year_month_day std::chrono::year_month_day_last \ std::chrono::year_month_weekday std::chrono::year_month_weekday_last These comparison operators are only available when using C++20. \endcompareswith

A QDate object represents a particular day, regardless of calendar, locale or other settings used when creating it or supplied by the system. It can report the year, month and day of the month that represent the day with respect to the proleptic Gregorian calendar or any calendar supplied as a QCalendar object. QDate objects should be passed by value rather than by reference to const; they simply package qint64.

A QDate object is typically created by giving the year, month, and day numbers explicitly. Note that QDate interprets year numbers less than 100 as presented, i.e., as years 1 through 99, without adding any offset. The static function currentDate() creates a QDate object containing the date read from the system clock. An explicit date can also be set using setDate(). The fromString() function returns a QDate given a string and a date format which is used to interpret the date within the string.

The year(), month(), and day() functions provide access to the year, month, and day numbers. When more than one of these values is needed, it is more efficient to call QCalendar::partsFromDate(), to save repeating (potentially expensive) calendrical calculations.

Also, dayOfWeek() and dayOfYear() functions are provided. The same information is provided in textual format by toString(). QLocale can map the day numbers to names, QCalendar can map month numbers to names.

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

You can increment (or decrement) a date by a given number of days using addDays(). Similarly you can use addMonths() and addYears(). The daysTo() function returns the number of days between two dates.

The daysInMonth() and daysInYear() functions return how many days there are in this date's month and year, respectively. The isLeapYear() function indicates whether a date is in a leap year. QCalendar can also supply this information, in some cases more conveniently.

Definition at line 28 of file qdatetime.h.

Member Typedef Documentation

◆ difference_type

using QDate::difference_type = qint64

Definition at line 32 of file qdatetime.h.

Constructor & Destructor Documentation

◆ QDate() [1/3]

QDate::QDate ( )

inlineconstexpr

Constructs a null date.

Null dates are invalid.

See also: isNull(), isValid()

Definition at line 34 of file qdatetime.h.

◆ QDate() [2/3]

QDate::QDate	(	int	y,
		int	m,
		int	d )

Constructs a date with year y, month m and day d.

The date is understood in terms of the Gregorian calendar. If the specified date is invalid, the date is not set and isValid() returns false.

Warning: Years 1 to 99 are interpreted as is. Year 0 is invalid.

See also: isValid(), QCalendar::dateFromParts()

Definition at line 448 of file qdatetime.cpp.

◆ QDate() [3/3]

QDate::QDate	(	int	y,
		int	m,
		int	d,
		QCalendar	cal )

Definition at line 455 of file qdatetime.cpp.

Member Function Documentation

◆ addDays()

QDate QDate::addDays ( qint64 ndays ) const

nodiscard

Returns a QDate object containing a date ndays later than the date of this object (or earlier if ndays is negative).

Returns a null date if the current date is invalid or the new date is out of range.

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

Definition at line 1423 of file qdatetime.cpp.

◆ addMonths() [1/2]

QDate QDate::addMonths ( int months ) const

nodiscard

Definition at line 1502 of file qdatetime.cpp.

◆ addMonths() [2/2]

QDate QDate::addMonths	(	int	months,
		QCalendar	cal ) const

nodiscard

Definition at line 1470 of file qdatetime.cpp.

◆ addYears() [1/2]

QDate QDate::addYears ( int years ) const

nodiscard

Definition at line 1569 of file qdatetime.cpp.

◆ addYears() [2/2]

QDate QDate::addYears	(	int	years,
		QCalendar	cal ) const

nodiscard

Definition at line 1546 of file qdatetime.cpp.

◆ currentDate()

QDate QDate::currentDate ( )

static

Returns the system clock's current date.

See also: QTime::currentTime(), QDateTime::currentDateTime()

◆ day() [1/2]

int QDate::day ( ) const

Definition at line 655 of file qdatetime.cpp.

◆ day() [2/2]

int QDate::day ( QCalendar cal ) const

Definition at line 641 of file qdatetime.cpp.

◆ dayOfWeek() [1/2]

int QDate::dayOfWeek ( ) const

Definition at line 689 of file qdatetime.cpp.

◆ dayOfWeek() [2/2]

int QDate::dayOfWeek ( QCalendar cal ) const

Definition at line 677 of file qdatetime.cpp.

◆ dayOfYear() [1/2]

int QDate::dayOfYear ( ) const

Definition at line 719 of file qdatetime.cpp.

◆ dayOfYear() [2/2]

int QDate::dayOfYear ( QCalendar cal ) const

Definition at line 705 of file qdatetime.cpp.

◆ daysInMonth() [1/2]

int QDate::daysInMonth ( ) const

Definition at line 754 of file qdatetime.cpp.

◆ daysInMonth() [2/2]

int QDate::daysInMonth ( QCalendar cal ) const

Definition at line 740 of file qdatetime.cpp.

◆ daysInYear() [1/2]

int QDate::daysInYear ( ) const

Definition at line 787 of file qdatetime.cpp.

◆ daysInYear() [2/2]

int QDate::daysInYear ( QCalendar cal ) const

Definition at line 775 of file qdatetime.cpp.

◆ daysTo()

qint64 QDate::daysTo ( QDate d ) const

Returns the number of days from this date to d (which is negative if d is earlier than this date).

Returns 0 if either date is invalid.

Example:

See also: addDays()

Definition at line 1600 of file qdatetime.cpp.

◆ endOfDay() [1/2]

QDateTime QDate::endOfDay ( ) const

Definition at line 1150 of file qdatetime.cpp.

◆ endOfDay() [2/2]

QDateTime QDate::endOfDay ( const QTimeZone & zone ) const

Definition at line 1120 of file qdatetime.cpp.

◆ fromJulianDay()

constexpr QDate QDate::fromJulianDay ( qint64 jd )

inlinestaticconstexpr

Converts the Julian day jd to a QDate.

See also: toJulianDay()

Definition at line 172 of file qdatetime.h.

◆ getDate()

void QDate::getDate	(	int *	year,
		int *	month,
		int *	day ) const

Since: 4.5

Extracts the date's year, month, and day, and assigns them to year, *month, and *day. The pointers may be null.

Returns 0 if the date is invalid.

Note: In Qt versions prior to 5.7, this function is marked as non-{const}.

See also: year(), month(), day(), isValid(), QCalendar::partsFromDate()

Definition at line 1398 of file qdatetime.cpp.

◆ isLeapYear()

bool QDate::isLeapYear ( int year )

static

Returns true if the specified year is a leap year in the Gregorian calendar; otherwise returns false.

See also: QCalendar::isLeapYear()

Definition at line 1957 of file qdatetime.cpp.

◆ isNull()

bool QDate::isNull ( ) const

inlineconstexpr

Returns true if the date is null; otherwise returns false.

A null date is invalid.

Note: The behavior of this function is equivalent to isValid().

See also: isValid()

Definition at line 73 of file qdatetime.h.

◆ isValid() [1/2]

bool QDate::isValid ( ) const

inlineconstexpr

Returns true if this date is valid; otherwise returns false.

See also: isNull(), QCalendar::isDateValid()

Definition at line 74 of file qdatetime.h.

◆ isValid() [2/2]

bool QDate::isValid	(	int	y,
		int	m,
		int	d )

static

Definition at line 1943 of file qdatetime.cpp.

◆ month() [1/2]

int QDate::month ( ) const

Definition at line 620 of file qdatetime.cpp.

◆ month() [2/2]

int QDate::month ( QCalendar cal ) const

Definition at line 606 of file qdatetime.cpp.

◆ setDate() [1/2]

bool QDate::setDate	(	int	year,
		int	month,
		int	day )

Since: 4.2

Sets this to represent the date, in the Gregorian calendar, with the given year, month and day numbers. Returns true if the resulting date is valid, otherwise it sets this to represent an invalid date and returns false.

See also: isValid(), QCalendar::dateFromParts()

Definition at line 1362 of file qdatetime.cpp.

◆ setDate() [2/2]

bool QDate::setDate	(	int	year,
		int	month,
		int	day,
		QCalendar	cal )

Since: 5.14

Sets this to represent the date, in the given calendar cal, with the given year, month and day numbers. Returns true if the resulting date is valid, otherwise it sets this to represent an invalid date and returns false.

See also: isValid(), QCalendar::dateFromParts()

Definition at line 1380 of file qdatetime.cpp.

◆ startOfDay() [1/2]

QDateTime QDate::startOfDay ( ) const

Definition at line 994 of file qdatetime.cpp.

◆ startOfDay() [2/2]

QDateTime QDate::startOfDay ( const QTimeZone & zone ) const

Definition at line 963 of file qdatetime.cpp.

◆ toJulianDay()

qint64 QDate::toJulianDay ( ) const

inlineconstexpr

Converts the date to a Julian day.

See also: fromJulianDay()

Definition at line 174 of file qdatetime.h.

◆ weekNumber()

int QDate::weekNumber ( int * yearNumber = nullptr ) const

Returns the ISO 8601 week number (1 to 53).

Returns 0 if the date is invalid. Otherwise, returns the week number for the date. If yearNumber is not \nullptr (its default), stores the year as {yearNumber}.

In accordance with ISO 8601, each week falls in the year to which most of its days belong, in the Gregorian calendar. As ISO 8601's week starts on Monday, this is the year in which the week's Thursday falls. Most years have 52 weeks, but some have 53.

Note: *{yearNumber} is not always the same as year(). For example, 1 January 2000 has week number 52 in the year 1999, and 31 December 2002 has week number 1 in the year 2003.

See also: isValid()

Definition at line 811 of file qdatetime.cpp.

◆ year() [1/2]

int QDate::year ( ) const

Definition at line 566 of file qdatetime.cpp.

◆ year() [2/2]

int QDate::year ( QCalendar cal ) const

Definition at line 552 of file qdatetime.cpp.

◆ comparesEqual

bool comparesEqual	(	const QDate &	lhs,
		const QDate &	rhs )

friend

Definition at line 209 of file qdatetime.h.

◆ compareThreeWay

Qt::strong_ordering compareThreeWay	(	const QDate &	lhs,
		const QDate &	rhs )

friend

Definition at line 212 of file qdatetime.h.

◆ dayOfYear() [1/2]

dayOfYear ( )

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

◆ dayOfYear() [2/2]

dayOfYear ( )

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

◆ endOfDay() [1/2]

endOfDay ( )

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since: 6.5

◆ endOfDay() [2/2]

endOfDay ( )

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since: 6.5

◆ operator++ [1/2]

QDate & operator++ ( QDate & date )

friend

Since: 6.11

The prefix {++} operator, adds a day to date and returns a reference to the modified date object.

See also: addDays(), operator--()

Definition at line 216 of file qdatetime.h.

◆ operator++ [2/2]

QDate operator++	(	QDate &	date,
		int	)

friend

Since: 6.11

The postfix {++} operator, adds a day to date and returns a copy of date with the previous date.

See also: addDays(), operator--()

Definition at line 228 of file qdatetime.h.

◆ operator-- [1/2]

QDate & operator-- ( QDate & date )

friend

Since: 6.11

The prefix {–} operator, subtracts a day from date and returns a reference to the modified date object.

See also: addDays(), operator++()

Definition at line 222 of file qdatetime.h.

◆ operator-- [2/2]

QDate operator--	(	QDate &	date,
		int	)

friend

Since: 6.11

The postfix {–} operator, subtracts a day from date and returns a copy of date with the next date.

See also: addDays(), operator++()

Definition at line 235 of file qdatetime.h.

◆ operator<<

QDataStream & operator<<	(	QDataStream &	out,
		QDate	date )

friend

Writes the date to stream out.

See also: {Serializing Qt Data Types}

Definition at line 6112 of file qdatetime.cpp.

◆ operator>>

QDataStream & operator>>	(	QDataStream &	in,
		QDate &	date )

friend

Reads a date from stream in into the date.

See also: {Serializing Qt Data Types}

Definition at line 6128 of file qdatetime.cpp.

◆ QDateTime

friend class QDateTime

friend

Definition at line 205 of file qdatetime.h.

◆ QDateTimeParser

friend class QDateTimeParser

friend

Definition at line 206 of file qdatetime.h.

◆ QDateTimePrivate

friend class QDateTimePrivate

friend

Definition at line 207 of file qdatetime.h.

◆ startOfDay() [1/2]

startOfDay ( )

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since: 6.5

◆ startOfDay() [2/2]

startOfDay ( )

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since: 6.5

The documentation for this class was generated from the following files:

qtbase/src/corelib/time/qdatetime.h (d9b675de61e8504a4ffa2f919962f1fce11e00ff)
qtbase/src/corelib/time/qdatetime.cpp (988b7b42fae84eb1c0a8febd0083630eb9177780)

Public Types

Public Member Functions

Static Public Member Functions

Friends

Related Symbols

Detailed Description

Member Typedef Documentation

◆ difference_type

Constructor & Destructor Documentation

◆ QDate() [1/3]

◆ QDate() [2/3]

◆ QDate() [3/3]

Member Function Documentation

◆ addDays()

◆ addMonths() [1/2]

◆ addMonths() [2/2]

◆ addYears() [1/2]

◆ addYears() [2/2]

◆ currentDate()

◆ day() [1/2]

◆ day() [2/2]

◆ dayOfWeek() [1/2]

◆ dayOfWeek() [2/2]

◆ dayOfYear() [1/2]

◆ dayOfYear() [2/2]

◆ daysInMonth() [1/2]

◆ daysInMonth() [2/2]

◆ daysInYear() [1/2]

◆ daysInYear() [2/2]

◆ daysTo()

◆ endOfDay() [1/2]

◆ endOfDay() [2/2]

◆ fromJulianDay()

◆ getDate()

◆ isLeapYear()

◆ isNull()

◆ isValid() [1/2]

◆ isValid() [2/2]

◆ month() [1/2]

◆ month() [2/2]

◆ setDate() [1/2]

◆ setDate() [2/2]

◆ startOfDay() [1/2]

◆ startOfDay() [2/2]

◆ toJulianDay()

◆ weekNumber()

◆ year() [1/2]

◆ year() [2/2]

Friends And Related Symbol Documentation

◆ comparesEqual

◆ compareThreeWay

◆ dayOfYear() [1/2]

◆ dayOfYear() [2/2]

◆ endOfDay() [1/2]

◆ endOfDay() [2/2]

◆ operator++ [1/2]

◆ operator++ [2/2]

◆ operator-- [1/2]

◆ operator-- [2/2]

◆ operator<<

◆ operator>>

◆ QDateTime

◆ QDateTimeParser

◆ QDateTimePrivate

◆ startOfDay() [1/2]

◆ startOfDay() [2/2]