diff options
| -rw-r--r-- | src/corelib/time/qdatetime.cpp | 46 |
1 files changed, 27 insertions, 19 deletions
diff --git a/src/corelib/time/qdatetime.cpp b/src/corelib/time/qdatetime.cpp index 248fd1d5ce..9c10e7fe39 100644 --- a/src/corelib/time/qdatetime.cpp +++ b/src/corelib/time/qdatetime.cpp @@ -362,9 +362,13 @@ static int fromOffsetString(QStringView offsetString, bool *valid) noexcept date format which is used to interpret the date within the string. The year(), month(), and day() functions provide access to the year, month, - and day numbers. Also, dayOfWeek() and dayOfYear() functions are - provided. The same information is provided in textual format by - toString(). The day and month numbers can be mapped to names using QLocale. + and day numbers. When more than one of these values is needed, it is more + efficient to call QCalendar::partsFromDate(), to save repeating (potentially + expensive) calendrical calculations. + + Also, dayOfWeek() and dayOfYear() functions are provided. The same + information is provided in textual format by toString(). QLocale can map the + day numbers to names, QCalendar can map month numbers to names. QDate provides a full set of operators to compare two QDate objects where smaller means earlier, and larger means later. @@ -374,19 +378,21 @@ static int fromOffsetString(QStringView offsetString, bool *valid) noexcept The daysTo() function returns the number of days between two dates. - The daysInMonth() and daysInYear() functions return how many days - there are in this date's month and year, respectively. The - isLeapYear() function indicates whether a date is in a leap year. + The daysInMonth() and daysInYear() functions return how many days there are + in this date's month and year, respectively. The isLeapYear() function + indicates whether a date is in a leap year. QCalendar can also supply this + information, in some cases more conveniently. \section1 Remarks \note All conversion to and from string formats is done using the C locale. For localized conversions, see QLocale. - \note There is no year 0 in the Gregorian calendar. Dates in that year are + In the Gregorian calendar, there is no year 0. Dates in that year are considered invalid. The year -1 is the year "1 before Christ" or "1 before - common era." The day before 1 January 1 CE, QDate(1, 1, 1), is 31 December 1 - BCE, QDate(-1, 12, 31). + common era." The day before 1 January 1 CE, QDate(1, 1, 1), is 31 December + 1 BCE, QDate(-1, 12, 31). Various other calendars behave similarly; see + QCalendar::hasYearZero(). \section2 Range of Valid Dates @@ -398,9 +404,10 @@ static int fromOffsetString(QStringView offsetString, bool *valid) noexcept Hebrew, Islamic or Chinese. The Julian Day number can be obtained using QDate::toJulianDay() and can be set using QDate::fromJulianDay(). - The range of dates able to be stored by QDate as a Julian Day number is - for technical reasons limited to between -784350574879 and 784354017364, - which means from before 2 billion BCE to after 2 billion CE. + The range of Julian Day numbers that QDate can represent is, for technical + reasons, limited to between -784350574879 and 784354017364, which means from + before 2 billion BCE to after 2 billion CE. This is more than seven times as + wide as the range of dates a QDateTime can represent. \sa QTime, QDateTime, QCalendar, QDateTime::YearRange, QDateEdit, QDateTimeEdit, QCalendarWidget */ @@ -473,7 +480,7 @@ QDate::QDate(int y, int m, int d, QCalendar cal) negative year numbers are used to indicate these years before year 1, with -1 indicating the year before 1. - \sa month(), day(), QCalendar::hasYearZero(), QCalendar::isProleptic() + \sa month(), day(), QCalendar::hasYearZero(), QCalendar::isProleptic(), QCalendar::partsFromDate() */ int QDate::year(QCalendar cal) const @@ -525,7 +532,7 @@ int QDate::year() const Returns 0 if the date is invalid. Note that some calendars may have more than 12 months in some years. - \sa year(), day() + \sa year(), day(), QCalendar::partsFromDate() */ int QDate::month(QCalendar cal) const @@ -558,7 +565,7 @@ int QDate::month() const Uses \a cal as calendar if supplied, else the Gregorian calendar (for which the return ranges from 1 to 31). Returns 0 if the date is invalid. - \sa year(), month(), dayOfWeek() + \sa year(), month(), dayOfWeek(), QCalendar::partsFromDate() */ int QDate::day(QCalendar cal) const @@ -592,7 +599,7 @@ int QDate::day() const if the date is invalid. Some calendars may give special meaning (e.g. intercallary days) to values greater than 7. - \sa day(), dayOfYear(), Qt::DayOfWeek + \sa day(), dayOfYear(), QCalendar::dayOfWeek(), Qt::DayOfWeek */ int QDate::dayOfWeek(QCalendar cal) const @@ -618,7 +625,7 @@ int QDate::dayOfWeek() const Uses \a cal as calendar if supplied, else the Gregorian calendar. Returns 0 if either the date or the first day of its year is invalid. - \sa day(), dayOfWeek() + \sa day(), dayOfWeek(), QCalendar::daysInYear() */ int QDate::dayOfYear(QCalendar cal) const @@ -651,7 +658,8 @@ int QDate::dayOfYear() const Uses \a cal as calendar if supplied, else the Gregorian calendar (for which the result ranges from 28 to 31). Returns 0 if the date is invalid. - \sa day(), daysInYear() + \sa day(), daysInYear(), QCalendar::daysInMonth(), + QCalendar::maximumDaysInMonth(), QCalendar::minimumDaysInMonth() */ int QDate::daysInMonth(QCalendar cal) const @@ -684,7 +692,7 @@ int QDate::daysInMonth() const Uses \a cal as calendar if supplied, else the Gregorian calendar (for which the result is 365 or 366). Returns 0 if the date is invalid. - \sa day(), daysInMonth() + \sa day(), daysInMonth(), QCalendar::daysInYear(), QCalendar::maximumMonthsInYear() */ int QDate::daysInYear(QCalendar cal) const |