QDateTime(3qt)QDateTime(3qt)NAME
QDateTime - Date and time functions
SYNOPSIS
All the functions in this class are reentrant when Qt is built with
thread support.</p>
#include <qdatetime.h>
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 )
RELATED FUNCTION DOCUMENTATION
QDataStream & operator<< ( QDataStream & s, const QDateTime & dt )
QDataStream & operator>> ( QDataStream & s, QDateTime & dt )
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 DOCUMENTATIONQDateTime::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 (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.
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 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 also QDate::isNull() and QTime::isNull().
bool QDateTime::isValid () const
Returns TRUE if both the date and the time are valid; otherwise returns
FALSE.
See also QDate::isValid() and QTime::isValid().
bool QDateTime::operator!= ( const QDateTime & dt ) const
Returns TRUE if this datetime is different from dt; otherwise returns
FALSE.
See also operator==().
bool QDateTime::operator< ( const QDateTime & dt ) const
Returns TRUE if this datetime is earlier than dt; otherwise returns
FALSE.
bool QDateTime::operator<= ( const QDateTime & dt ) const
Returns TRUE if this datetime is earlier than or equal to dt; otherwise
returns FALSE.
bool QDateTime::operator== ( const QDateTime & dt ) const
Returns TRUE if this datetime is equal to dt; otherwise returns FALSE.
See also operator!=().
bool QDateTime::operator> ( const QDateTime & dt ) const
Returns TRUE if this datetime is later than dt; otherwise returns
FALSE.
bool QDateTime::operator>= ( const QDateTime & dt ) const
Returns TRUE if this datetime is later than or equal to dt; otherwise
returns 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 xmas( QDate(dt.date().year(),12,24), QTime(17,00) );
qDebug( "There are %d seconds to Christmas", dt.secsTo(xmas) );
See also addSecs(), daysTo(), and QTime::secsTo().
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, Qt::TimeSpec ts )
Sets the date and time to ts time (Qt::LocalTime or Qt::UTC) given the
number of seconds that have passed since 1970-01-01T00:00:00,
Coordinated Universal Time (UTC). On systems that do not support
timezones this function will behave as if local time were UTC.
On Windows, only a subset of secsSince1Jan1970UTC values are supported,
as Windows starts counting from 1980.
See also toTime_t().
void QDateTime::setTime_t ( uint secsSince1Jan1970UTC )
This is an overloaded member function, provided for convenience. It
behaves essentially like the above function.
Convenience function that sets the date and time to local time based on
the given UTC time.
QTime QDateTime::time () const
Returns the time part of the datetime.
See also setTime() and date().
QString QDateTime::toString ( const QString & format ) const
Returns the datetime as a string. The format parameter determines the
format of the result string.
These expressions may be used for the date:
<center>.nf
</center>
These expressions may be used for the time:
<center>.nf
</center>
All other input characters will be ignored.
Example format strings (assumed that the QDateTime is
21<small><sup>st</sup></small> May 2001 14:13:09)
<center>.nf
</center>
If the datetime is an invalid datetime, then QString::null will be
returned.
See also QDate::toString() and QTime::toString().
QString QDateTime::toString ( Qt::DateFormat f = Qt::TextDate ) const
This is an overloaded member function, provided for convenience. It
behaves essentially like the above function.
Returns the datetime as a string. The f parameter determines the format
of the string.
If f is Qt::TextDate, the string format is "Wed May 20 03:40:13 1998"
(using QDate::shortDayName(), QDate::shortMonthName(), and
QTime::toString() to generate the string, so the day and month names
will have localized names).
If f is Qt::ISODate, the string format corresponds to the ISO 8601
extended specification for representations of dates and times, which is
YYYY-MM-DDTHH:MM:SS.
If f is Qt::LocalDate, the string format depends on the locale settings
of the system.
If the format f is invalid or the datetime is invalid, toString()
returns a null string.
See also QDate::toString() and QTime::toString().
uint QDateTime::toTime_t () const
Returns the datetime as the number of seconds that have passed since
1970-01-01T00:00:00, Coordinated Universal Time (UTC).
On systems that do not support timezones, this function will behave as
if local time were UTC.
See also setTime_t().
RELATED FUNCTION DOCUMENTATIONQDataStream & operator<< ( QDataStream & s, const QDateTime & dt )
Writes the datetime dt to the stream s.
See also Format of the QDataStream operators.
QDataStream & operator>> ( QDataStream & s, QDateTime & dt )
Reads a datetime from the stream s into dt.
See also Format of the QDataStream operators.
SEE ALSO
http://doc.trolltech.com/qdatetime.html
http://www.trolltech.com/faq/tech.html
COPYRIGHT
Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com. See the
license file included in the distribution for a complete license
statement.
AUTHOR
Generated automatically from the source code.
BUGS
If you find a bug in Qt, please report it as described in
http://doc.trolltech.com/bughowto.html. Good bug reports help us to
help you. Thank you.
The definitive Qt documentation is provided in HTML format; it is
located at $QTDIR/doc/html and can be read using Qt Assistant or with a
web browser. This man page is provided as a convenience for those users
who prefer man pages, although this format is not officially supported
by Trolltech.
If you find errors in this manual page, please report them to qt-
bugs@trolltech.com. Please include the name of the manual page
(qdatetime.3qt) and the Qt version (3.3.8).
Trolltech AS 2 February 2007 QDateTime(3qt)