# QDateTime Class Reference

The QDateTime class combines QDate and QTime into a single class. More...

`#include <qdatetime.h>`

List of all member functions.

## Public Members

- QDateTime ()
- QDateTime ( const QDate & )
- QDateTime ( const QDate &, const QTime & )
- bool isNull () const
- bool isValid () const
- QDate date () const
- QTime time () const
- void setDate ( const QDate & date )
- void setTime ( const QTime & time )
- void setTime_t ( uint secsSince1Jan1970UTC )
- QString toString () const
- QDateTime addDays ( int days ) const
- QDateTime addSecs ( int secs ) const
- int daysTo ( const QDateTime & ) const
- int secsTo ( const QDateTime & ) 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 ()

## Related Functions

(Note that these are not member functions.)

- QDataStream & operator<< (QDataStream & s, const QDateTime & dt)
- QDataStream & operator>> (QDataStream & s, QDateTime & dt)

## Detailed Description

The QDateTime class combines QDate and QTime into a single class.

QDateTime provides high precision date and time functions since it can work with Gregorian dates up to about year 8000.

Most countries that use the Gregorian calendar switched to it between 1550 and 1920.

See also: QDate and QTime.

## 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 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 the datetime plus ndays days.

See also: daysTo().

### QDateTime QDateTime::addSecs ( int nsecs ) const

Returns the datetime plus nsecs seconds.

See also: secsTo().

### QDateTime QDateTime::currentDateTime () `[static]`

Returns the current datetime.

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

### QDate QDateTime::date () const

Returns the date part of this datetime.

See also: time().

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

Returns the number of days from this datetime to dt, which is negative if dt is in the past.

See also: addDays() and secsTo().

### bool QDateTime::isNull () const

Returns TRUE if both the date and the time are null. A null date is invalid.

See also: QDate::isNull() and QTime::isNull().

### bool QDateTime::isValid () const

Returns TRUE if both the date and the time are value.

See also: QDate::isValid() and QTime::isValid().

### bool QDateTime::operator!= ( const QDateTime & dt ) const

Returns TRUE if this datetime is different from dt, or FALSE if they are equal.

See also: operator==().

### bool QDateTime::operator< ( const QDateTime & dt ) const

Returns TRUE if this datetime is before dt, otherwise FALSE.

### bool QDateTime::operator<= ( const QDateTime & dt ) const

Returns TRUE if this datetime is before or equal to dt, otherwise FALSE.

### bool QDateTime::operator== ( const QDateTime & dt ) const

Returns TRUE if this datetime is equal to dt, or FALSE if they are different.

See also: operator!=().

### bool QDateTime::operator> ( const QDateTime & dt ) const

Returns TRUE if this datetime is after dt, otherwise FALSE.

### bool QDateTime::operator>= ( const QDateTime & dt ) const

Returns TRUE if this datetime is equal to or after dt, otherwise FALSE.

### int QDateTime::secsTo ( const QDateTime & dt ) const

Returns the number of seconds from this datetime to dt, which is negative if t is in the past.

Example:

        QDateTime dt = QDateTime::currentDateTime();
        QDateTime x( QDate(dt.year(),12,24), QTime(17,00) );
        debug( "There are %d seconds to Christmas", dt.secsTo(x) );

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

### void QDateTime::setDate ( const QDate & date )

Sets the date part of this datetime.

See also: setTime().

### void QDateTime::setTime ( const QTime & time )

Sets the time part of this datetime.

See also: setDate().

### void QDateTime::setTime_t ( uint secsSince1Jan1970UTC )

Sets the local date and time given the number of seconds that have passed since 00:00:00 on January 1, 1970, Coordinated Universal Time (UTC). On systems that do not support timezones this function will behave as if local time were UTC.

### QTime QDateTime::time () const

Returns the time part of this datetime.

See also: date().

### QString QDateTime::toString () const

Returns the datetime as a string.

The string format is "Sat May 20 1995 03:40:13".

## Related Functions

### QDataStream & operator<< (QDataStream & s, const QDateTime & dt)

Writes a datetime to the stream.

Serialization format: [QDate QTime].

### QDataStream & operator>> (QDataStream & s, QDateTime & dt)

Reads a datetime from the stream.

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This file is part of the Qt toolkit, copyright © 1995-99 Troll Tech, all rights reserved.

It was generated from the following files:

- qdatetime.h: 1998/08/25
- qdatetime.cpp: 1999/02/15