QDateTime Class Reference
The QDateTime class provides date and time functions.
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#include <qdatetime.h>
List of all member functions.
Public Members
QDateTime ( const QDate & date, const QTime & time )
void
setDate ( const QDate & date )
void
setTime ( const QTime & time )
QString
toString ( Qt::DateFormat f = Qt::TextDate ) const
QDateTime
addDays ( int ndays ) 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
Static Public Members
QDateTime
fromString ( const QString & s, Qt::DateFormat f = Qt::TextDate )
Related Functions
QDataStream &
operator<< ( QDataStream & s, const QDateTime & dt )
QDataStream &
operator>> ( QDataStream & s, QDateTime & dt )
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 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.
See also isValid().
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 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 () [static]
Returns the current datetime, as reported by the system clock.
See also QDate::currentDate() and QTime::currentTime().
Example: listviews/listviews.cpp.
QDate QDateTime::date () const
Returns the date part of this datetime.
See also setDate() and time().
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() and secsTo().
QDateTime QDateTime::fromString ( const QString & s, Qt::DateFormat f = Qt::TextDate ) [static]
Returns the representation s as a QDateTime using the format f, or
an invalid datetime if this is not possible.
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 valid.
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 earlier than dt, otherwise FALSE.
bool QDateTime::operator<= ( const QDateTime & dt ) const
Returns TRUE if this datetime is earlier than 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 later than dt, otherwise FALSE.
bool QDateTime::operator>= ( const QDateTime & dt ) const
Returns TRUE if this datetime is later than or equal to dt,
otherwise 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() and QTime::secsTo().
Example: ftpclient/ftpview.cpp.
void QDateTime::setDate ( const QDate & date )
Sets the date part of this datetime to date.
See also date() and setTime().
void QDateTime::setTime ( const QTime & time )
Sets the time part of this datetime to time.
See also time() and 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.
Note that Microsoft Windows supports only a limited range of values for
secsSince1Jan1970UTC.
QTime QDateTime::time () const
Returns the time part of this datetime.
See also setTime() and date().
QString QDateTime::toString ( Qt::DateFormat f = Qt::TextDate ) const
Returns the datetime as a string. The f parameter determines
the format of the string.
If f is Qt::TextDate, the string format is "Sat May 20 03:40:13
1998" (using QDate::dayName(), QDate::monthName(), and
QTime::toString() to generate the string).
If f is Qt::ISODate, the string format corresponds to the ISO
8601 specification for representations of dates and times, which is
YYYY-MM-DDTHH:MM:SS.
If the format f is invalid, toString() returns a null string.
See also QDate::toString() and QTime::toString.
Related Functions
Writes the datetime dt to the stream s.
See also Format of the QDataStream operators.
Reads a datetime from the stream s into dt.
See also Format of the QDataStream operators.
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