1QDateTime(3qt) QDateTime(3qt)
2
6 QDateTime - Date and time functions
7
9 All the functions in this class are reentrant when Qt is built with
10 thread support.</p>
11 #include <qdatetime.h>
13 Public Members
15 QDateTime ()
16 QDateTime ( const QDate & date )
17 QDateTime ( const QDate & date, const QTime & time )
18 bool isNull () const
19 bool isValid () const
20 QDate date () const
21 QTime time () const
22 uint toTime_t () const
23 void setDate ( const QDate & date )
24 void setTime ( const QTime & time )
25 void setTime_t ( uint secsSince1Jan1970UTC )
26 void setTime_t ( uint secsSince1Jan1970UTC, Qt::TimeSpec ts )
27 QString toString ( Qt::DateFormat f = Qt::TextDate ) const
28 QString toString ( const QString & format ) const
29 QDateTime addDays ( int ndays ) const
30 QDateTime addMonths ( int nmonths ) const
31 QDateTime addYears ( int nyears ) const
32 QDateTime addSecs ( int nsecs ) const
33 int daysTo ( const QDateTime & dt ) const
34 int secsTo ( const QDateTime & dt ) const
35 bool operator== ( const QDateTime & dt ) const
36 bool operator!= ( const QDateTime & dt ) const
37 bool operator< ( const QDateTime & dt ) const
38 bool operator<= ( const QDateTime & dt ) const
39 bool operator> ( const QDateTime & dt ) const
40 bool operator>= ( const QDateTime & dt ) const
41 Static Public Members
43 QDateTime currentDateTime ()
44 QDateTime currentDateTime ( Qt::TimeSpec ts )
45 QDateTime fromString ( const QString & s, Qt::DateFormat f =
46 Qt::TextDate )
47
49 QDataStream & operator<< ( QDataStream & s, const QDateTime & dt )
50 QDataStream & operator>> ( QDataStream & s, QDateTime & dt )
51
53 The QDateTime class provides date and time functions.
54 A QDateTime object contains a calendar date and a clock time (a"
56 datetime"). It is a combination of the QDate and QTime classes. It can
57 read the current datetime from the system clock. It provides functions
58 for comparing datetimes and for manipulating a datetime by adding a
59 number of seconds, days, months or years.
60 A QDateTime object is typically created either by giving a date and
62 time explicitly in the constructor, or by using the static function
63 currentDateTime(), which returns a QDateTime object set to the system
64 clock's time. The date and time can be changed with setDate() and
65 setTime(). A datetime can also be set using the setTime_t() function,
66 which takes a POSIX-standard "number of seconds since 00:00:00 on
67 January 1, 1970" value. The fromString() function returns a QDateTime
68 given a string and a date format which is used to interpret the date
69 within the string.
70 The date() and time() functions provide access to the date and time
72 parts of the datetime. The same information is provided in textual
73 format by the toString() function.
74 QDateTime provides a full set of operators to compare two QDateTime
76 objects where smaller means earlier and larger means later.
77 You can increment (or decrement) a datetime by a given number of
79 seconds using addSecs() or days using addDays(). Similarly you can use
80 addMonths() and addYears(). The daysTo() function returns the number of
81 days between two datetimes, and secsTo() returns the number of seconds
82 between two datetimes.
83 The range of a datetime object is constrained to the ranges of the
85 QDate and QTime objects which it embodies.
86 See also QDate, QTime, QDateTimeEdit, and Time and Date.
88
91 Constructs a null datetime (i.e. null date and null time). A null
92 datetime is invalid, since the date is invalid.
93 See also isValid().
95
97 Constructs a datetime with date date and null (but valid) time
98 (00:00:00.000).
99
101 Constructs a datetime with date date and time time.
102
104 Returns a QDateTime object containing a datetime ndays days later than
105 the datetime of this object (or earlier if ndays is negative).
106 See also daysTo(), addMonths(), addYears(), and addSecs().
108
110 Returns a QDateTime object containing a datetime nmonths months later
111 than the datetime of this object (or earlier if nmonths is negative).
112 See also daysTo(), addDays(), addYears(), and addSecs().
114
116 Returns a QDateTime object containing a datetime nsecs seconds later
117 than the datetime of this object (or earlier if nsecs is negative).
118 See also secsTo(), addDays(), addMonths(), and addYears().
120 Example: listviews/listviews.cpp.
122
124 Returns a QDateTime object containing a datetime nyears years later
125 than the datetime of this object (or earlier if nyears is negative).
126 See also daysTo(), addDays(), addMonths(), and addSecs().
128
130 Returns the current datetime, as reported by the system clock, for the
131 TimeSpec ts. The default TimeSpec is LocalTime.
132 See also QDate::currentDate(), QTime::currentTime(), and Qt::TimeSpec.
134 Example: listviews/listviews.cpp.
136
138 This is an overloaded member function, provided for convenience. It
139 behaves essentially like the above function.
140 Returns the current datetime, as reported by the system clock.
142 See also QDate::currentDate() and QTime::currentTime().
144
146 Returns the date part of the datetime.
147 See also setDate() and time().
149
151 Returns the number of days from this datetime to dt (which is negative
152 if dt is earlier than this datetime).
153 See also addDays() and secsTo().
155
157 Qt::TextDate ) [static]
158 Returns the QDateTime represented by the string s, using the format f,
159 or an invalid datetime if this is not possible.
160 Note for Qt::TextDate: It is recommended that you use the English short
162 month names (e.g. "Jan"). Although localized month names can also be
163 used, they depend on the user's locale settings.
164 Warning: Note that Qt::LocalDate cannot be used here.
166
168 Returns TRUE if both the date and the time are null; otherwise returns
169 FALSE. A null datetime is invalid.
170 See also QDate::isNull() and QTime::isNull().
172
174 Returns TRUE if both the date and the time are valid; otherwise returns
175 FALSE.
176 See also QDate::isValid() and QTime::isValid().
178
180 Returns TRUE if this datetime is different from dt; otherwise returns
181 FALSE.
182 See also operator==().
184
186 Returns TRUE if this datetime is earlier than dt; otherwise returns
187 FALSE.
188
190 Returns TRUE if this datetime is earlier than or equal to dt; otherwise
191 returns FALSE.
192
194 Returns TRUE if this datetime is equal to dt; otherwise returns FALSE.
195 See also operator!=().
197
199 Returns TRUE if this datetime is later than dt; otherwise returns
200 FALSE.
201
203 Returns TRUE if this datetime is later than or equal to dt; otherwise
204 returns FALSE.
205
207 Returns the number of seconds from this datetime to dt (which is
208 negative if dt is earlier than this datetime).
209 Example:
211 QDateTime dt = QDateTime::currentDateTime();
213 QDateTime xmas( QDate(dt.date().year(),12,24), QTime(17,00) );
214 qDebug( "There are %d seconds to Christmas", dt.secsTo(xmas) );
215 See also addSecs(), daysTo(), and QTime::secsTo().
217
219 Sets the date part of this datetime to date.
220 See also date() and setTime().
222
224 Sets the time part of this datetime to time.
225 See also time() and setDate().
227
229 Sets the date and time to ts time (Qt::LocalTime or Qt::UTC) given the
230 number of seconds that have passed since 1970-01-01T00:00:00,
231 Coordinated Universal Time (UTC). On systems that do not support
232 timezones this function will behave as if local time were UTC.
233 On Windows, only a subset of secsSince1Jan1970UTC values are supported,
235 as Windows starts counting from 1980.
236 See also toTime_t().
238
240 This is an overloaded member function, provided for convenience. It
241 behaves essentially like the above function.
242 Convenience function that sets the date and time to local time based on
244 the given UTC time.
245
247 Returns the time part of the datetime.
248 See also setTime() and date().
250
252 Returns the datetime as a string. The format parameter determines the
253 format of the result string.
254 These expressions may be used for the date:
256 <center>.nf
258 </center>
260 These expressions may be used for the time:
262 <center>.nf
264 </center>
266 All other input characters will be ignored.
268 Example format strings (assumed that the QDateTime is
270 21<small><sup>st</sup></small> May 2001 14:13:09)
271 <center>.nf
273 </center>
275 If the datetime is an invalid datetime, then QString::null will be
277 returned.
278 See also QDate::toString() and QTime::toString().
280
282 This is an overloaded member function, provided for convenience. It
283 behaves essentially like the above function.
284 Returns the datetime as a string. The f parameter determines the format
286 of the string.
287 If f is Qt::TextDate, the string format is "Wed May 20 03:40:13 1998"
289 (using QDate::shortDayName(), QDate::shortMonthName(), and
290 QTime::toString() to generate the string, so the day and month names
291 will have localized names).
292 If f is Qt::ISODate, the string format corresponds to the ISO 8601
294 extended specification for representations of dates and times, which is
295 YYYY-MM-DDTHH:MM:SS.
296 If f is Qt::LocalDate, the string format depends on the locale settings
298 of the system.
299 If the format f is invalid or the datetime is invalid, toString()
301 returns a null string.
302 See also QDate::toString() and QTime::toString().
304
306 Returns the datetime as the number of seconds that have passed since
307 1970-01-01T00:00:00, Coordinated Universal Time (UTC).
308 On systems that do not support timezones, this function will behave as
310 if local time were UTC.
311 See also setTime_t().
313
316 Writes the datetime dt to the stream s.
317 See also Format of the QDataStream operators.
319
321 Reads a datetime from the stream s into dt.
322 See also Format of the QDataStream operators.
324
327 http://doc.trolltech.com/qdatetime.html
328 http://www.trolltech.com/faq/tech.html
329
331 Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com. See the
332 license file included in the distribution for a complete license
333 statement.
334
336 Generated automatically from the source code.
337
339 If you find a bug in Qt, please report it as described in
340 http://doc.trolltech.com/bughowto.html. Good bug reports help us to
341 help you. Thank you.
342 The definitive Qt documentation is provided in HTML format; it is
344 located at $QTDIR/doc/html and can be read using Qt Assistant or with a
345 web browser. This man page is provided as a convenience for those users
346 who prefer man pages, although this format is not officially supported
347 by Trolltech.
348 If you find errors in this manual page, please report them to qt-
350 bugs@trolltech.com. Please include the name of the manual page
351 (qdatetime.3qt) and the Qt version (3.3.8).
352Trolltech AS 2 February 2007 QDateTime(3qt)