GI.Gtk.Objects.Calendar

Calendar is a widget that displays a Gregorian calendar, one month at a time. It can be created with calendarNew.

The month and year currently displayed can be altered with calendarSelectMonth. The exact day can be selected from the displayed month using calendarSelectDay.

To place a visual marker on a particular day, use calendarMarkDay and to remove the marker, calendarUnmarkDay. Alternative, all marks can be cleared with calendarClearMarks.

The way in which the calendar itself is displayed can be altered using calendarSetDisplayOptions.

The selected date can be retrieved from a Calendar using calendarGetDate.

Users should be aware that, although the Gregorian calendar is the legal calendar in most countries, it was adopted progressively between 1582 and 1929. Display before these dates is likely to be historically incorrect.

Exported types

newtype Calendar

Memory-managed wrapper type.

Constructors

Calendar (ManagedPtr Calendar)

Instances

Eq Calendar

Defined in GI.Gtk.Objects.Calendar

Methods

(==) :: Calendar -> Calendar -> Bool

(/=) :: Calendar -> Calendar -> Bool

IsGValue Calendar

Convert Calendar to and from GValue with toGValue and fromGValue.

Defined in GI.Gtk.Objects.Calendar

Methods

toGValue :: Calendar -> IO GValue

fromGValue :: GValue -> IO Calendar

ManagedPtrNewtype Calendar

Defined in GI.Gtk.Objects.Calendar

Methods

toManagedPtr :: Calendar -> ManagedPtr Calendar

TypedObject Calendar

Defined in GI.Gtk.Objects.Calendar

Methods

glibType :: IO GType

GObject Calendar

Defined in GI.Gtk.Objects.Calendar

HasParentTypes Calendar

Defined in GI.Gtk.Objects.Calendar

type ParentTypes Calendar

Defined in GI.Gtk.Objects.Calendar

type ParentTypes Calendar = '[Widget, Object, ImplementorIface, Buildable]

class (GObject o, IsDescendantOf Calendar o) => IsCalendar o

Type class for types which can be safely cast to Calendar, for instance with toCalendar.

Instances

(GObject o, IsDescendantOf Calendar o) => IsCalendar o

Defined in GI.Gtk.Objects.Calendar

toCalendar :: (MonadIO m, IsCalendar o) => o -> m Calendar

Cast to Calendar, for types for which this is known to be safe. For general casts, use castTo.

Methods

Overloaded methods

clearMarks

calendarClearMarks

Arguments

:: (HasCallStack, MonadIO m, IsCalendar a)

=> a

calendar: a Calendar

-> m ()

Remove all visual markers.

getDate

calendarGetDate

Arguments

:: (HasCallStack, MonadIO m, IsCalendar a)

=> a

calendar: a Calendar

-> m (Word32, Word32, Word32)

Obtains the selected date from a Calendar.

getDayIsMarked

calendarGetDayIsMarked

Arguments

:: (HasCallStack, MonadIO m, IsCalendar a)

=> a

calendar: a Calendar

-> Word32

day: the day number between 1 and 31.

-> m Bool

Returns: whether the day is marked.

Returns if the day of the calendar is already marked.

Since: 3.0

getDetailHeightRows

calendarGetDetailHeightRows

Arguments

:: (HasCallStack, MonadIO m, IsCalendar a)

=> a

calendar: a Calendar.

-> m Int32

Returns: The height of detail cells, in rows.

Queries the height of detail cells, in rows. See Calendar:detail-width-chars.

Since: 2.14

getDetailWidthChars

calendarGetDetailWidthChars

Arguments

:: (HasCallStack, MonadIO m, IsCalendar a)

=> a

calendar: a Calendar.

-> m Int32

Returns: The width of detail cells, in characters.

Queries the width of detail cells, in characters. See Calendar:detail-width-chars.

Since: 2.14

getDisplayOptions

calendarGetDisplayOptions

Arguments

:: (HasCallStack, MonadIO m, IsCalendar a)

=> a

calendar: a Calendar

-> m [CalendarDisplayOptions]

Returns: the display options.

Returns the current display options of calendar.

Since: 2.4

markDay

calendarMarkDay

Arguments

:: (HasCallStack, MonadIO m, IsCalendar a)

=> a

calendar: a Calendar

-> Word32

day: the day number to mark between 1 and 31.

-> m ()

Places a visual marker on a particular day.

new

calendarNew

Arguments

:: (HasCallStack, MonadIO m)

=> m Calendar

Returns: a newly Calendar widget

Creates a new calendar, with the current date being selected.

selectDay

calendarSelectDay

Arguments

:: (HasCallStack, MonadIO m, IsCalendar a)

=> a

calendar: a Calendar.

-> Word32

day: the day number between 1 and 31, or 0 to unselect the currently selected day.

-> m ()

Selects a day from the current month.

selectMonth

calendarSelectMonth

Arguments

:: (HasCallStack, MonadIO m, IsCalendar a)

=> a

calendar: a Calendar

-> Word32

month: a month number between 0 and 11.

-> Word32

year: the year the month is in.

-> m ()

Shifts the calendar to a different month.

setDetailFunc

calendarSetDetailFunc

Arguments

:: (HasCallStack, MonadIO m, IsCalendar a)

=> a

calendar: a Calendar.

-> CalendarDetailFunc

func: a function providing details for each day.

-> m ()

Installs a function which provides Pango markup with detail information for each day. Examples for such details are holidays or appointments. That information is shown below each day when Calendar:show-details is set. A tooltip containing with full detail information is provided, if the entire text should not fit into the details area, or if Calendar:show-details is not set.

The size of the details area can be restricted by setting the Calendar:detail-width-chars and Calendar:detail-height-rows properties.

Since: 2.14

setDetailHeightRows

calendarSetDetailHeightRows

Arguments

:: (HasCallStack, MonadIO m, IsCalendar a)

=> a

calendar: a Calendar.

-> Int32

rows: detail height in rows.

-> m ()

Updates the height of detail cells. See Calendar:detail-height-rows.

Since: 2.14

setDetailWidthChars

calendarSetDetailWidthChars

Arguments

:: (HasCallStack, MonadIO m, IsCalendar a)

=> a

calendar: a Calendar.

-> Int32

chars: detail width in characters.

-> m ()

Updates the width of detail cells. See Calendar:detail-width-chars.

Since: 2.14

setDisplayOptions

calendarSetDisplayOptions

Arguments

:: (HasCallStack, MonadIO m, IsCalendar a)

=> a

calendar: a Calendar

-> [CalendarDisplayOptions]

flags: the display options to set

-> m ()

Sets display options (whether to display the heading and the month headings).

Since: 2.4

unmarkDay

calendarUnmarkDay

Arguments

:: (HasCallStack, MonadIO m, IsCalendar a)

=> a

calendar: a Calendar.

-> Word32

day: the day number to unmark between 1 and 31.

-> m ()

Removes the visual marker from a particular day.

Properties

day

The selected day (as a number between 1 and 31, or 0 to unselect the currently selected day). This property gets initially set to the current day.

constructCalendarDay :: (IsCalendar o, MonadIO m) => Int32 -> m (GValueConstruct o)

Construct a GValueConstruct with valid value for the “day” property. This is rarely needed directly, but it is used by new.

getCalendarDay :: (MonadIO m, IsCalendar o) => o -> m Int32

Get the value of the “day” property. When overloading is enabled, this is equivalent to

get calendar #day

setCalendarDay :: (MonadIO m, IsCalendar o) => o -> Int32 -> m ()

Set the value of the “day” property. When overloading is enabled, this is equivalent to

set calendar [ #day := value ]

detailHeightRows

Height of a detail cell, in rows. A value of 0 allows any width. See calendarSetDetailFunc.

Since: 2.14

constructCalendarDetailHeightRows :: (IsCalendar o, MonadIO m) => Int32 -> m (GValueConstruct o)

Construct a GValueConstruct with valid value for the “detail-height-rows” property. This is rarely needed directly, but it is used by new.

getCalendarDetailHeightRows :: (MonadIO m, IsCalendar o) => o -> m Int32

Get the value of the “detail-height-rows” property. When overloading is enabled, this is equivalent to

get calendar #detailHeightRows

setCalendarDetailHeightRows :: (MonadIO m, IsCalendar o) => o -> Int32 -> m ()

Set the value of the “detail-height-rows” property. When overloading is enabled, this is equivalent to

set calendar [ #detailHeightRows := value ]

detailWidthChars

Width of a detail cell, in characters. A value of 0 allows any width. See calendarSetDetailFunc.

Since: 2.14

constructCalendarDetailWidthChars :: (IsCalendar o, MonadIO m) => Int32 -> m (GValueConstruct o)

Construct a GValueConstruct with valid value for the “detail-width-chars” property. This is rarely needed directly, but it is used by new.

getCalendarDetailWidthChars :: (MonadIO m, IsCalendar o) => o -> m Int32

Get the value of the “detail-width-chars” property. When overloading is enabled, this is equivalent to

get calendar #detailWidthChars

setCalendarDetailWidthChars :: (MonadIO m, IsCalendar o) => o -> Int32 -> m ()

Set the value of the “detail-width-chars” property. When overloading is enabled, this is equivalent to

set calendar [ #detailWidthChars := value ]

month

The selected month (as a number between 0 and 11). This property gets initially set to the current month.

constructCalendarMonth :: (IsCalendar o, MonadIO m) => Int32 -> m (GValueConstruct o)

Construct a GValueConstruct with valid value for the “month” property. This is rarely needed directly, but it is used by new.

getCalendarMonth :: (MonadIO m, IsCalendar o) => o -> m Int32

Get the value of the “month” property. When overloading is enabled, this is equivalent to

get calendar #month

setCalendarMonth :: (MonadIO m, IsCalendar o) => o -> Int32 -> m ()

Set the value of the “month” property. When overloading is enabled, this is equivalent to

set calendar [ #month := value ]

noMonthChange

Determines whether the selected month can be changed.

Since: 2.4

constructCalendarNoMonthChange :: (IsCalendar o, MonadIO m) => Bool -> m (GValueConstruct o)

Construct a GValueConstruct with valid value for the “no-month-change” property. This is rarely needed directly, but it is used by new.

getCalendarNoMonthChange :: (MonadIO m, IsCalendar o) => o -> m Bool

Get the value of the “no-month-change” property. When overloading is enabled, this is equivalent to

get calendar #noMonthChange

setCalendarNoMonthChange :: (MonadIO m, IsCalendar o) => o -> Bool -> m ()

Set the value of the “no-month-change” property. When overloading is enabled, this is equivalent to

set calendar [ #noMonthChange := value ]

showDayNames

Determines whether day names are displayed.

Since: 2.4

constructCalendarShowDayNames :: (IsCalendar o, MonadIO m) => Bool -> m (GValueConstruct o)

Construct a GValueConstruct with valid value for the “show-day-names” property. This is rarely needed directly, but it is used by new.

getCalendarShowDayNames :: (MonadIO m, IsCalendar o) => o -> m Bool

Get the value of the “show-day-names” property. When overloading is enabled, this is equivalent to

get calendar #showDayNames

setCalendarShowDayNames :: (MonadIO m, IsCalendar o) => o -> Bool -> m ()

Set the value of the “show-day-names” property. When overloading is enabled, this is equivalent to

set calendar [ #showDayNames := value ]

showDetails

Determines whether details are shown directly in the widget, or if they are available only as tooltip. When this property is set days with details are marked.

Since: 2.14

constructCalendarShowDetails :: (IsCalendar o, MonadIO m) => Bool -> m (GValueConstruct o)

Construct a GValueConstruct with valid value for the “show-details” property. This is rarely needed directly, but it is used by new.

getCalendarShowDetails :: (MonadIO m, IsCalendar o) => o -> m Bool

Get the value of the “show-details” property. When overloading is enabled, this is equivalent to

get calendar #showDetails

setCalendarShowDetails :: (MonadIO m, IsCalendar o) => o -> Bool -> m ()

Set the value of the “show-details” property. When overloading is enabled, this is equivalent to

set calendar [ #showDetails := value ]

showHeading

Determines whether a heading is displayed.

Since: 2.4

constructCalendarShowHeading :: (IsCalendar o, MonadIO m) => Bool -> m (GValueConstruct o)

Construct a GValueConstruct with valid value for the “show-heading” property. This is rarely needed directly, but it is used by new.

getCalendarShowHeading :: (MonadIO m, IsCalendar o) => o -> m Bool

Get the value of the “show-heading” property. When overloading is enabled, this is equivalent to

get calendar #showHeading

setCalendarShowHeading :: (MonadIO m, IsCalendar o) => o -> Bool -> m ()

Set the value of the “show-heading” property. When overloading is enabled, this is equivalent to

set calendar [ #showHeading := value ]

showWeekNumbers

Determines whether week numbers are displayed.

Since: 2.4

constructCalendarShowWeekNumbers :: (IsCalendar o, MonadIO m) => Bool -> m (GValueConstruct o)

Construct a GValueConstruct with valid value for the “show-week-numbers” property. This is rarely needed directly, but it is used by new.

getCalendarShowWeekNumbers :: (MonadIO m, IsCalendar o) => o -> m Bool

Get the value of the “show-week-numbers” property. When overloading is enabled, this is equivalent to

get calendar #showWeekNumbers

setCalendarShowWeekNumbers :: (MonadIO m, IsCalendar o) => o -> Bool -> m ()

Set the value of the “show-week-numbers” property. When overloading is enabled, this is equivalent to

set calendar [ #showWeekNumbers := value ]

year

The selected year. This property gets initially set to the current year.

constructCalendarYear :: (IsCalendar o, MonadIO m) => Int32 -> m (GValueConstruct o)

Construct a GValueConstruct with valid value for the “year” property. This is rarely needed directly, but it is used by new.

getCalendarYear :: (MonadIO m, IsCalendar o) => o -> m Int32

Get the value of the “year” property. When overloading is enabled, this is equivalent to

get calendar #year

setCalendarYear :: (MonadIO m, IsCalendar o) => o -> Int32 -> m ()

Set the value of the “year” property. When overloading is enabled, this is equivalent to

set calendar [ #year := value ]

Signals

daySelected

type C_CalendarDaySelectedCallback = Ptr () -> Ptr () -> IO ()

Type for the callback on the (unwrapped) C side.

type CalendarDaySelectedCallback = IO ()

Emitted when the user selects a day.

afterCalendarDaySelected :: (IsCalendar a, MonadIO m) => a -> CalendarDaySelectedCallback -> m SignalHandlerId

Connect a signal handler for the daySelected signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after calendar #daySelected callback

genClosure_CalendarDaySelected :: MonadIO m => CalendarDaySelectedCallback -> m (GClosure C_CalendarDaySelectedCallback)

Wrap the callback into a GClosure.

mk_CalendarDaySelectedCallback :: C_CalendarDaySelectedCallback -> IO (FunPtr C_CalendarDaySelectedCallback)

Generate a function pointer callable from C code, from a C_CalendarDaySelectedCallback.

noCalendarDaySelectedCallback :: Maybe CalendarDaySelectedCallback

A convenience synonym for Nothing :: Maybe CalendarDaySelectedCallback.

onCalendarDaySelected :: (IsCalendar a, MonadIO m) => a -> CalendarDaySelectedCallback -> m SignalHandlerId

Connect a signal handler for the daySelected signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on calendar #daySelected callback

wrap_CalendarDaySelectedCallback :: CalendarDaySelectedCallback -> C_CalendarDaySelectedCallback

Wrap a CalendarDaySelectedCallback into a C_CalendarDaySelectedCallback.

daySelectedDoubleClick

type C_CalendarDaySelectedDoubleClickCallback = Ptr () -> Ptr () -> IO ()

Type for the callback on the (unwrapped) C side.

type CalendarDaySelectedDoubleClickCallback = IO ()

Emitted when the user double-clicks a day.

afterCalendarDaySelectedDoubleClick :: (IsCalendar a, MonadIO m) => a -> CalendarDaySelectedDoubleClickCallback -> m SignalHandlerId

Connect a signal handler for the daySelectedDoubleClick signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after calendar #daySelectedDoubleClick callback

genClosure_CalendarDaySelectedDoubleClick :: MonadIO m => CalendarDaySelectedDoubleClickCallback -> m (GClosure C_CalendarDaySelectedDoubleClickCallback)

Wrap the callback into a GClosure.

mk_CalendarDaySelectedDoubleClickCallback :: C_CalendarDaySelectedDoubleClickCallback -> IO (FunPtr C_CalendarDaySelectedDoubleClickCallback)

Generate a function pointer callable from C code, from a C_CalendarDaySelectedDoubleClickCallback.

noCalendarDaySelectedDoubleClickCallback :: Maybe CalendarDaySelectedDoubleClickCallback

A convenience synonym for Nothing :: Maybe CalendarDaySelectedDoubleClickCallback.

onCalendarDaySelectedDoubleClick :: (IsCalendar a, MonadIO m) => a -> CalendarDaySelectedDoubleClickCallback -> m SignalHandlerId

Connect a signal handler for the daySelectedDoubleClick signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on calendar #daySelectedDoubleClick callback

wrap_CalendarDaySelectedDoubleClickCallback :: CalendarDaySelectedDoubleClickCallback -> C_CalendarDaySelectedDoubleClickCallback

Wrap a CalendarDaySelectedDoubleClickCallback into a C_CalendarDaySelectedDoubleClickCallback.

monthChanged

type C_CalendarMonthChangedCallback = Ptr () -> Ptr () -> IO ()

Type for the callback on the (unwrapped) C side.

type CalendarMonthChangedCallback = IO ()

Emitted when the user clicks a button to change the selected month on a calendar.

afterCalendarMonthChanged :: (IsCalendar a, MonadIO m) => a -> CalendarMonthChangedCallback -> m SignalHandlerId

Connect a signal handler for the monthChanged signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after calendar #monthChanged callback

genClosure_CalendarMonthChanged :: MonadIO m => CalendarMonthChangedCallback -> m (GClosure C_CalendarMonthChangedCallback)

Wrap the callback into a GClosure.

mk_CalendarMonthChangedCallback :: C_CalendarMonthChangedCallback -> IO (FunPtr C_CalendarMonthChangedCallback)

Generate a function pointer callable from C code, from a C_CalendarMonthChangedCallback.

noCalendarMonthChangedCallback :: Maybe CalendarMonthChangedCallback

A convenience synonym for Nothing :: Maybe CalendarMonthChangedCallback.

onCalendarMonthChanged :: (IsCalendar a, MonadIO m) => a -> CalendarMonthChangedCallback -> m SignalHandlerId

Connect a signal handler for the monthChanged signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on calendar #monthChanged callback

wrap_CalendarMonthChangedCallback :: CalendarMonthChangedCallback -> C_CalendarMonthChangedCallback

Wrap a CalendarMonthChangedCallback into a C_CalendarMonthChangedCallback.

nextMonth

type C_CalendarNextMonthCallback = Ptr () -> Ptr () -> IO ()

Type for the callback on the (unwrapped) C side.

type CalendarNextMonthCallback = IO ()

Emitted when the user switched to the next month.

afterCalendarNextMonth :: (IsCalendar a, MonadIO m) => a -> CalendarNextMonthCallback -> m SignalHandlerId

Connect a signal handler for the nextMonth signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after calendar #nextMonth callback

genClosure_CalendarNextMonth :: MonadIO m => CalendarNextMonthCallback -> m (GClosure C_CalendarNextMonthCallback)

Wrap the callback into a GClosure.

mk_CalendarNextMonthCallback :: C_CalendarNextMonthCallback -> IO (FunPtr C_CalendarNextMonthCallback)

Generate a function pointer callable from C code, from a C_CalendarNextMonthCallback.

noCalendarNextMonthCallback :: Maybe CalendarNextMonthCallback

A convenience synonym for Nothing :: Maybe CalendarNextMonthCallback.

onCalendarNextMonth :: (IsCalendar a, MonadIO m) => a -> CalendarNextMonthCallback -> m SignalHandlerId

Connect a signal handler for the nextMonth signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on calendar #nextMonth callback

wrap_CalendarNextMonthCallback :: CalendarNextMonthCallback -> C_CalendarNextMonthCallback

Wrap a CalendarNextMonthCallback into a C_CalendarNextMonthCallback.

nextYear

type C_CalendarNextYearCallback = Ptr () -> Ptr () -> IO ()

Type for the callback on the (unwrapped) C side.

type CalendarNextYearCallback = IO ()

Emitted when user switched to the next year.

afterCalendarNextYear :: (IsCalendar a, MonadIO m) => a -> CalendarNextYearCallback -> m SignalHandlerId

Connect a signal handler for the nextYear signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after calendar #nextYear callback

genClosure_CalendarNextYear :: MonadIO m => CalendarNextYearCallback -> m (GClosure C_CalendarNextYearCallback)

Wrap the callback into a GClosure.

mk_CalendarNextYearCallback :: C_CalendarNextYearCallback -> IO (FunPtr C_CalendarNextYearCallback)

Generate a function pointer callable from C code, from a C_CalendarNextYearCallback.

noCalendarNextYearCallback :: Maybe CalendarNextYearCallback

A convenience synonym for Nothing :: Maybe CalendarNextYearCallback.

onCalendarNextYear :: (IsCalendar a, MonadIO m) => a -> CalendarNextYearCallback -> m SignalHandlerId

Connect a signal handler for the nextYear signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on calendar #nextYear callback

wrap_CalendarNextYearCallback :: CalendarNextYearCallback -> C_CalendarNextYearCallback

Wrap a CalendarNextYearCallback into a C_CalendarNextYearCallback.

prevMonth

type C_CalendarPrevMonthCallback = Ptr () -> Ptr () -> IO ()

Type for the callback on the (unwrapped) C side.

type CalendarPrevMonthCallback = IO ()

Emitted when the user switched to the previous month.

afterCalendarPrevMonth :: (IsCalendar a, MonadIO m) => a -> CalendarPrevMonthCallback -> m SignalHandlerId

Connect a signal handler for the prevMonth signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after calendar #prevMonth callback

genClosure_CalendarPrevMonth :: MonadIO m => CalendarPrevMonthCallback -> m (GClosure C_CalendarPrevMonthCallback)

Wrap the callback into a GClosure.

mk_CalendarPrevMonthCallback :: C_CalendarPrevMonthCallback -> IO (FunPtr C_CalendarPrevMonthCallback)

Generate a function pointer callable from C code, from a C_CalendarPrevMonthCallback.

noCalendarPrevMonthCallback :: Maybe CalendarPrevMonthCallback

A convenience synonym for Nothing :: Maybe CalendarPrevMonthCallback.

onCalendarPrevMonth :: (IsCalendar a, MonadIO m) => a -> CalendarPrevMonthCallback -> m SignalHandlerId

Connect a signal handler for the prevMonth signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on calendar #prevMonth callback

wrap_CalendarPrevMonthCallback :: CalendarPrevMonthCallback -> C_CalendarPrevMonthCallback

Wrap a CalendarPrevMonthCallback into a C_CalendarPrevMonthCallback.

prevYear

type C_CalendarPrevYearCallback = Ptr () -> Ptr () -> IO ()

Type for the callback on the (unwrapped) C side.

type CalendarPrevYearCallback = IO ()

Emitted when user switched to the previous year.

afterCalendarPrevYear :: (IsCalendar a, MonadIO m) => a -> CalendarPrevYearCallback -> m SignalHandlerId

Connect a signal handler for the prevYear signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after calendar #prevYear callback

genClosure_CalendarPrevYear :: MonadIO m => CalendarPrevYearCallback -> m (GClosure C_CalendarPrevYearCallback)

Wrap the callback into a GClosure.

mk_CalendarPrevYearCallback :: C_CalendarPrevYearCallback -> IO (FunPtr C_CalendarPrevYearCallback)

Generate a function pointer callable from C code, from a C_CalendarPrevYearCallback.

noCalendarPrevYearCallback :: Maybe CalendarPrevYearCallback

A convenience synonym for Nothing :: Maybe CalendarPrevYearCallback.

onCalendarPrevYear :: (IsCalendar a, MonadIO m) => a -> CalendarPrevYearCallback -> m SignalHandlerId

Connect a signal handler for the prevYear signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on calendar #prevYear callback

wrap_CalendarPrevYearCallback :: CalendarPrevYearCallback -> C_CalendarPrevYearCallback

Wrap a CalendarPrevYearCallback into a C_CalendarPrevYearCallback.