QDateTime

Section: Misc. Reference Manual Pages (3qt)
Updated: 2 February 2007
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NAME

QDateTime - Date and time functions

SYNOPSIS

All the functions in this class are reentrant when Qt is built with thread support.</p>

Public Members

QDateTime ()

QDateTime ( const QDate & date )

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

bool isNull () const

bool isValid () const

QDate date () const

QTime time () const

uint toTime_t () const

void setDate ( const QDate & date )

void setTime ( const QTime & time )

void setTime_t ( uint secsSince1Jan1970UTC )

void setTime_t ( uint secsSince1Jan1970UTC, Qt::TimeSpec ts )

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

QString toString ( const QString & format ) const

QDateTime addDays ( int ndays ) const

QDateTime addMonths ( int nmonths ) const

QDateTime addYears ( int nyears ) const

QDateTime addSecs ( int nsecs ) const

int daysTo ( const QDateTime & dt ) const

int secsTo ( const QDateTime & dt ) const

bool operator== ( const QDateTime & dt ) const

bool operator!= ( const QDateTime & dt ) const

bool operator< ( const QDateTime & dt ) const

bool operator<= ( const QDateTime & dt ) const

bool operator> ( const QDateTime & dt ) const

bool operator>= ( const QDateTime & dt ) const

Static Public Members

QDateTime currentDateTime ()

QDateTime currentDateTime ( Qt::TimeSpec ts )

QDateTime fromString ( const QString & s, Qt::DateFormat f = Qt::TextDate )

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(), which 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() function, which takes a POSIX-standard "number of seconds since 00:00:00 on January 1, 1970" value. The fromString() function returns a QDateTime given a string and a date format which is used to interpret the date within the string.

The date() and time() functions 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 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, and secsTo() returns the number of seconds between two datetimes.

The range of a datetime object is constrained to the ranges of the QDate and QTime objects which it embodies.

See also QDate, QTime, QDateTimeEdit, and Time and Date.

MEMBER FUNCTION DOCUMENTATION

QDateTime::QDateTime ()

Constructs a null datetime (i.e. null date and null time). A null datetime is invalid, since the date is invalid.

QDateTime::QDateTime ( const QDate & date )

Constructs a datetime with date date and null (but valid) time (00:00:00.000).

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

Constructs a datetime with date date and time time.

QDateTime QDateTime::addDays ( int ndays ) const

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

See also daysTo(), addMonths(), addYears(), and addSecs().

QDateTime QDateTime::addMonths ( int nmonths ) const

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

See also daysTo(), addDays(), addYears(), and addSecs().

QDateTime QDateTime::addSecs ( int nsecs ) const

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

See also secsTo(), addDays(), addMonths(), and addYears().

Example: listviews/listviews.cpp.

QDateTime QDateTime::addYears ( int nyears ) const

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

See also daysTo(), addDays(), addMonths(), and addSecs().

QDateTime QDateTime::currentDateTime ( Qt::TimeSpec ts ) [static]

Returns the current datetime, as reported by the system clock, for the TimeSpec ts. The default TimeSpec is LocalTime.

See also QDate::currentDate(), QTime::currentTime(), and Qt::TimeSpec.

Example: listviews/listviews.cpp.

QDateTime QDateTime::currentDateTime () [static]

This is an overloaded member function, provided for convenience. It behaves essentially like the above function.

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

See also QDate::currentDate() and QTime::currentTime().

QDate QDateTime::date () const

Returns the date part of the datetime.

int QDateTime::daysTo ( const QDateTime & dt ) const

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

QDateTime QDateTime::fromString ( const QString & s, Qt::DateFormat f = Qt::TextDate ) [static]

Returns the QDateTime represented by the string s, using the format f, or an invalid datetime if this is not possible.

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

Warning: Note that Qt::LocalDate cannot be used here.

bool QDateTime::isNull () const

Returns TRUE if both the date and the time are null; otherwise returns FALSE. A null datetime is invalid.

See