QDateTime Class Reference

The QDateTime class provides date and time functions. More...

#include <qdatetime.h>

Public Member Functions
	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 Member Functions
static QDateTime	currentDateTime ()

Private Attributes
QDate	d
QTime	t

Friends
Q_EXPORT QDataStream &	operator<< (QDataStream &, const QDateTime &)
Q_EXPORT QDataStream &	operator>> (QDataStream &, QDateTime &)

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 or days.

A QDateTime object is typically created either by giving a date and time explicitly, or by using the static function currentTime(), which makes a QDateTime object which contains the system's clock time.

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. A datetime is considered smaller than another if it is earlier than the other.

The datetime a given number of days or seconds later than a given datetime can be found using the addDays() and addSecs() functions. Correspondingly, the number of days or seconds between two times can be found using the daysTo() or secsTo() functions.

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 limitations regarding range and resolution mentioned in the QDate and QTime documentation apply for QDateTime also.

See also

QDate, QTime

Definition at line 161 of file qdatetime.h.

Constructor & Destructor Documentation

QDateTime::QDateTime ( )

inline

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

See also

isValid()

Definition at line 164 of file qdatetime.h.

{}                              // set null date and null time

QDateTime::QDateTime

(

const QDate &

date

)

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

Definition at line 1068 of file qdatetime.cpp.

    : d(date)
{
}

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

Constructs a datetime with date date and time time.

Definition at line 1077 of file qdatetime.cpp.

    : d(date), t(time)
{
}

Member Function Documentation

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(), addSecs()

Definition at line 1192 of file qdatetime.cpp.

{
    return QDateTime( d.addDays(ndays), t );
}

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()

Definition at line 1205 of file qdatetime.cpp.

{
    uint dd = d.jd;
    int  tt = t.ds;
    int  sign = 1;
    if ( nsecs < 0 ) {
        nsecs = -nsecs;
        sign = -1;
    }
    if ( nsecs >= (int)SECS_PER_DAY ) {
        dd += sign*(nsecs/SECS_PER_DAY);
        nsecs %= SECS_PER_DAY;
    }
    tt += sign*nsecs*1000;
    if ( tt < 0 ) {
        tt = MSECS_PER_DAY - tt - 1;
        dd -= tt / MSECS_PER_DAY;
        tt = tt % MSECS_PER_DAY;
        tt = MSECS_PER_DAY - tt - 1;
    } else if ( tt >= (int)MSECS_PER_DAY ) {
        dd += ( tt / MSECS_PER_DAY );
        tt = tt % MSECS_PER_DAY;
    }
    QDateTime ret;
    ret.t.ds = tt;
    ret.d.jd = dd;
    return ret;
}

QDateTime QDateTime::currentDateTime ( )

static

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

See also

QDate::currentDate(), QTime::currentTime()

Definition at line 1340 of file qdatetime.cpp.

{
    QDate cd = QDate::currentDate();
    QTime ct;
    if ( QTime::currentTime(&ct) )              // too close to midnight?
        cd = QDate::currentDate();              // YES! time for some midnight
                                                // voodoo, fetch date again
    return QDateTime( cd, ct );
}

QDate QDateTime::date ( ) const

inline

Returns the date part of this datetime.

See also

setDate(), time()

Definition at line 171 of file qdatetime.h.

{ return d; }

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).

See also

addDays(), secsTo()

Definition at line 1241 of file qdatetime.cpp.

{
    return d.daysTo( dt.d );
}

bool QDateTime::isNull ( ) const

inline

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

See also

QDate::isNull(), QTime::isNull()

Definition at line 168 of file qdatetime.h.

{ return d.isNull() && t.isNull(); }

bool QDateTime::isValid ( ) const

inline

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

See also

QDate::isValid(), QTime::isValid()

Definition at line 169 of file qdatetime.h.

{ return d.isValid() && t.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==()

Definition at line 1283 of file qdatetime.cpp.

{
    return  t != dt.t || d != dt.d;
}

bool QDateTime::operator<

(

const QDateTime &

dt

)

const

Returns TRUE if this datetime is earlier than dt, otherwise FALSE.

Definition at line 1292 of file qdatetime.cpp.

{
    if ( d < dt.d )
        return TRUE;
    return d == dt.d ? t < dt.t : FALSE;
}

bool QDateTime::operator<=

(

const QDateTime &

dt

)

const

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

Definition at line 1304 of file qdatetime.cpp.

{
    if ( d < dt.d )
        return TRUE;
    return d == dt.d ? t <= dt.t : 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!=()

Definition at line 1272 of file qdatetime.cpp.

{
    return  t == dt.t && d == dt.d;
}

bool QDateTime::operator>

(

const QDateTime &

dt

)

const

Returns TRUE if this datetime is later than dt, otherwise FALSE.

Definition at line 1315 of file qdatetime.cpp.

{
    if ( d > dt.d )
        return TRUE;
    return d == dt.d ? t > dt.t : FALSE;
}

bool QDateTime::operator>=

(

const QDateTime &

dt

)

const

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

Definition at line 1327 of file qdatetime.cpp.

{
    if ( d > dt.d )
        return TRUE;
    return d == dt.d ? t >= dt.t : FALSE;
}

int QDateTime::secsTo

(

const QDateTime &

dt

)

const

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

Example:

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

See also

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

Definition at line 1260 of file qdatetime.cpp.

{
    return t.secsTo(dt.t) + d.daysTo(dt.d)*SECS_PER_DAY;
}

void QDateTime::setDate ( const QDate &  date )

inline

Sets the date part of this datetime.

See also

date(), setTime()

Definition at line 173 of file qdatetime.h.

{ d=date; }

void QDateTime::setTime ( const QTime &  time )

inline

Sets the time part of this datetime.

See also

time(), setDate()

Definition at line 174 of file qdatetime.h.

{ t=time; }

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.

Note that Microsoft Windows supports only a limited range of values for secsSince1Jan1970UTC.

Definition at line 1142 of file qdatetime.cpp.

{
    time_t tmp = (time_t) secsSince1Jan1970UTC;
    tm *tM = localtime( &tmp );
    if ( !tM ) {
        tM = gmtime( &tmp );
        if ( !tM ) {
            d.jd = QDate::greg2jul( 1970, 1, 1 );
            t.ds = 0;
            return;
        }
    }
    d.jd = QDate::greg2jul( tM->tm_year + 1900, tM->tm_mon + 1, tM->tm_mday );
    t.ds = MSECS_PER_HOUR*tM->tm_hour + MSECS_PER_MIN*tM->tm_min +
            1000*tM->tm_sec;
}

QTime QDateTime::time ( ) const

inline

Returns the time part of this datetime.

See also

setTime(), date()

Definition at line 172 of file qdatetime.h.

{ return t; }

QString QDateTime::toString

(

)

const

Returns the datetime as a string.

The string format is "Sat May 20 03:40:13 1998".

This function uses QDate::dayName(), QDate::monthName(), and QTime::toString() to generate the string.

Definition at line 1170 of file qdatetime.cpp.

{
    QString buf = d.dayName(d.dayOfWeek());
    buf += ' ';
    buf += d.monthName(d.month());
    buf += ' ';
    buf += QString().setNum(d.day());
    buf += ' ';
    buf += t.toString();
    buf += ' ';
    buf += QString().setNum(d.year());
    return buf;
}

Friends And Related Function Documentation

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

friend

Writes a datetime to the stream.

See also

Format of the QDataStream operators

Definition at line 1417 of file qdatetime.cpp.

{
    return s << dt.d << dt.t;
}

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

friend

Reads a datetime from the stream.

See also

Format of the QDataStream operators

Definition at line 1429 of file qdatetime.cpp.

{
    s >> dt.d >> dt.t;
    return s;
}

Member Data Documentation

QDate QDateTime::d

private

Definition at line 194 of file qdatetime.h.

QTime QDateTime::t

private

Definition at line 195 of file qdatetime.h.

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

• doxygen-1.8.11/qtools/qdatetime.h
• doxygen-1.8.11/qtools/qdatetime.cpp