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57    Time Manager

Palm OS® Programmer's API Reference

Palm OS® 68K SDK

     

This chapter provides reference material for the time manager.

The header file DateTime.h declares the API that this chapter describes. For more information on the time manager, see the section "Time" in the Palm OS Programmer's Companion, vol. I.

Time Manager Data Structures ^TOP^

The time manager uses these structures to store information.

DateFormatType Enum ^TOP^

Purpose

The DateFormatType enum specifies the different display formats for date values.

Prototype

typedef enum {
dfMDYWithSlashes,
dfDMYWithSlashes,
dfDMYWithDots,
dfDMYWithDashes,
dfYMDWithSlashes,
dfYMDWithDots,
dfYMDWithDashes,
dfMDYLongWithComma,
dfDMYLong,
dfDMYLongWithDot,
dfDMYLongNoDay,
dfDMYLongWithComma,
dfYMDLongWithDot,
dfYMDLongWithSpace,
dfMYMed,
dfMYMedNoPost,
dfMDYWithDashes
} DateFormatType;

Constants

dfMDYWithSlashes
The month, day, and year numbers separated by slashes. For example, 12/31/95.
This is considered a short format.
dfDMYWithSlashes
The day, month, and year numbers separated by slashes. For example, 31/12/95.
This is considered a short format.
dfDMYWithDots
The day, month, and year numbers separated by dots. For example, 31.12.95.
This is considered a short format.
dfDMYWithDashes
The day, month, and year numbers separated by dashes. For example, 31-12-95.
This is considered a short format.
dfYMDWithSlashes
The year, month, and day numbers separated by slashes. For example, 95/12/31.
This is considered a short format.
dfYMDWithDots
The year, month, and day numbers separated by dots. For example, 95.12.31.
This is considered a short format.
dfYMDWithDashes
The year, month, and day numbers separated by dashes. For example, 95-12-31.
This is considered a short format.
dfMDYLongWithComma
The month, day, and year in long format, with a comma. For example, Dec 31, 1995.
This is considered a long format.
dfDMYLong
The month, day, and year in long format. For example, 31 Dec 1995.
This is considered a long format.
dfDMYLongWithDot
The month, day, and year in long format, with a dot. For example, 31. Dec 1995.
This is considered a long format.
dfDMYLongNoDay
The month and year in long format. For example, Dec 1995.
This is considered a long format.
dfDMYLongWithComma
The day, month, and year in long format, with a comma. For example, 31 Dec, 1995.
This is considered a long format.
dfYMDLongWithDot
The year, month, and day in long format with dot separators. For example, 1995.12.31.
This is considered a long format.
dfYMDLongWithSpace
The year, month, and day in long format with space separators. For example, 1995 Dec 31.
This is considered a long format.
dfMYMed
The month in long format with the two-digit year, preceded by an apostrophe. For example, Dec '95.
This is considered a medium format.
dfMYMedNoPost
The month in long format with the two-digit year. For example, Dec 95.
This is considered a medium format.
dfMDYWithDashes
The month, day, and year numbers separated by dashes. For example, 12-31-95.
This is considered a short format.

Compatibility

The dfMDYWithDashes constant is defined in Palm OS® 4.0 and higher.

DateTimeType Struct ^TOP^

Purpose

The DateTimeType structure represents a date and time value.

Prototype

typedef struct{
Int16 second;
Int16 minute;
Int16 hour;
Int16 day;
Int16 month;
Int16 year;
Int16 weekDay;
} DateTimeType
typedef DateTimeType *DateTimePtr;

Fields

second
The number of seconds. This is a value between 0 and 59.
minute
The number of minutes. This is a value between 0 and 59.
hour
The number of hours. This is a value between 0 and 23.
day
The day number. This is a value between 1 and 31.
month
The month number. This is a value between 1 and 12.
year
The year number.
weekDay
The day number. This represents the number of days since Sunday and is thus a value between 0 and 6.

DateType Struct ^TOP^

Purpose

The DateType structure represents a date value.

Prototype

typedef struct{
UInt16 year:7;
UInt16 month:4;
UInt16 day:5;
} DateType;
typedef DateType *DatePtr;

Fields

year
The number of years since 1904.
Note that this is the format used on Macintosh computers.
month
The month number. This is a value between 1 and 12.
day
The day number. This is a value between 1 and 31.

DaylightSavingsTypes Enum ^TOP^

Purpose

The DaylightSavingsTypes enum specifies the different forms of daylight savings times that you can specify for date and time values.

Note that the table uses "DST" to represent daylight savings time.

Prototype

typedef enum {
dsNone,
dsUSA,
dsAustralia,
dsWesternEuropean,
dsMiddleEuropean,
dsEasternEuropean,
dsGreatBritain,
dsRumania,
dsTurkey,
dsAustraliaShifted
} DaylightSavingsTypes;

Constants

dsNone
No DST (daylight savings time)
dsUSA
U.S.A. DST
dsAustralia
Australian DST
dsWesternEuropean
Western European DST
dsMiddleEuropean
Middle European DST
dsEasternEuropean
Eastern European DST
dsGreatBritain
Great Britain and Eire DST
dsRumania
Rumanian DST
dsTurkey
Turkish DST
dsAustraliaShifted
Australian DST, with the 1986 shift

Compatibility

If 4.0 New Feature Set is present, this data type is obsolete. In versions 4.0 and higher, Palm OS represents daylight savings time as an integer value that gives the number of minutes to add to the current time for daylight savings time.

DayOfMonthType Enum ^TOP^

Purpose

The DayOfMonth enum specifies the different day-of-the-week numeric values that are returned by the DayOfMonth() function. These values are used to represent repeating appointments that occur on specific days of the month; for example, the first Friday or the third Tuesday of each month.

Prototype

typedef enum {
dom1stSun, dom1stMon, dom1stTue, dom1stWen,
dom1stThu, dom1stFri, dom1stSat,
dom2ndSun, dom2ndMon, dom2ndTue, dom2ndWen,
dom2ndThu, dom2ndFri, dom2ndSat,
dom3rdSun, dom3rdMon, dom3rdTue, dom3rdWen,
dom3rdThu, dom3rdFri, dom3rdSat,
dom4thSun, dom4thMon, dom4thTue, dom4thWen,
dom4thThu, dom4thFri, dom4thSat,
domLastSun, domLastMon, domLastTue,
domLastWen, domLastThu, domLastFri,
domLastSat
} DayOfWeekType;

Constants

dom1stSun
The first Sunday of the month.
dom1stMon
The first Monday of the month.
dom1stTue
The first Tuesday of the month.
dom1stWen
The first Wednesday of the month.
dom1stThu
The first Thursday of the month.
dom1stFri
The first Friday of the month.
dom1stSat
The first Saturday of the month.
dom2ndSun
The second Sunday of the month.
dom2ndMon
The second Monday of the month.
dom2ndTue
The second Tuesday of the month.
dom2ndWen
The second Wednesday of the month.
dom2ndThu
The second Thursday of the month.
dom2ndFri
The second Friday of the month.
dom2ndSat
The second Saturday of the month.
dom3rdSun
The third Sunday of the month.
dom3rdMon
The third Monday of the month.
dom3rdTue
The third Tuesday of the month.
dom3rdWen
The third Wednesday of the month.
dom3rdThu
The third Thursday of the month.
dom3rdFri
The third Friday of the month.
dom3rdSat
The third Saturday of the month.
dom4thSun
The fourth Sunday of the month.
dom4thMon
The fourth Monday of the month.
dom4thTue
The fourth Tuesday of the month.
dom4thWen
The fourth Wednesday of the month.
dom4thThu
The fourth Thursday of the month.
dom4thFri
The fourth Friday of the month.
dom4thSat
The fourth Saturday of the month.
domLastSun
The last Sunday of the month.
domLastMon
The last Monday of the month.
domLastTue
The last Tuesday of the month.
domLastWen
The last Wednesday of the month.
domLastThu
The last Thursday of the month.
domLastFri
The last Friday of the month.
domLastSat
The last Saturday of the month.

Compatibility

On Palm OS versions earlier than 4.0, this type was named DayOfWeekType.

TimeFormatType Enum ^TOP^

Purpose

The TimeFormatType enum specifies the different display formats for time values.

Prototype

typedef enum {
tfColon,
tfColonAMPM,
tfColon24h,
tfDot,
tfDotAMPM,
tfDot24h,
tfHoursAMPM,
tfHours24h,
tfComma24h,
} TimeFormatType;
typedef TimeFormatType *TimeFormatPtr;

Constants

tfColon
The hour and minutes separated by a colon character. For example, 1:00.
tfColonAMPM
The hour and minutes separated by a colon and followed by an AM/PM indication. For example, 1:00 pm.
tfColon24h
The 24-hour time with the hour and minutes separated by a colon character. For example, 13:00.
tfDot
The hour and minutes separated by a dot character. For example, 1.00.
tfDotAMPM
The hour and minutes separated by a period and followed by an AM/PM indication. For example, 1.00 pm.
tfDot24h
The 24-hour time with the hour and minutes separated by a dot character. For example, 13.00.
tfHoursAMPM
The hour value followed by an AM/PM indication. For example, 1 pm.
tfHours24h
The 24-hour value, followed by an AM/PM indication. For example, 13.
tfComma24h
The 24-hour time with the hour and minutes separated by a comma character. For example, 13,00.

TimeType Struct ^TOP^

Purpose

The TimeType structure represents a time value.

Prototype

typedef struct {
UInt8hours;
UInt8minutes;
} TimeType;
typedef TimeType *TimePtr;

Fields

hours
The number of hours. This is a value between 0 and 23.
minutes
The number of minutes. This is value between 0 and 59.

Time Manager Constants ^TOP^

The following table shows the constants that represent the maximum lengths of strings returned by the date and time formatting routines DateToAscii(), DateToDOWDMFormat(), and TimeToAscii().

Constant

Value

Description

dateStringLength

9

Maximum length of the string returned by DateToAscii for short date formats.

longDateStrLength

15

Maximum length of the string returned by DateToAscii for medium and long date formats.

timeStringLength

9

Maximum length of the string returned by TimeToAscii.

dowDateStringLength

19

Maximum length of the string returned by DateToDOWDMFormat for short date formats.

dowLongDateStrLength

25

Maximum length of the string returned by DateToDOWDMFormat for both medium and long date formats.

Time Manager Functions ^TOP^

DateAdjust Function ^TOP^

Purpose

Return a new date +/- the days adjustment.

Declared In

DateTime.h

Prototype

void DateAdjust (
   DateType*dateP,
   Int32adjustment
)

Parameters

dateP
A pointer to a DateType structure with the date to be adjusted.
adjustment
The number of days by which to adjust the date.

Returns

Returns nothing. Upon return, dateP contains the adjusted date.

Comments

This function advances the date and manages month and year wrapping conditions.

See Also

TimAdjust()

DateDaysToDate Function ^TOP^

Purpose

Converts a date specified as the number of days since January 1, 1904 to a DateType structure.

Declared In

DateTime.h

Prototype

void DateDaysToDate (
   UInt32days,
   DateType*dateP
)

Parameters

days
The number of days since 1/1/1904.
dateP
A pointer to a DateType structure that is updated with the computed date values.

Returns

Returns nothing. Upon return, the date information is returned in the structure referenced by the date parameter.

See Also

DateSecondsToDate(), DateToDays()

DateSecondsToDate Function ^TOP^

Purpose

Converts a date specified as the number of seconds since January 1, 1904 to a DateType structure.

Declared In

DateTime.h

Prototype

void DateSecondsToDate (
   UInt32seconds,
   DateType*dateP
)

Parameters

seconds
The number of seconds since 1/1/1904.
dateP
A pointer to a DateType structure that is updated with the computed date values.

Returns

Returns nothing. The structure referenced by the date parameter is updated with the date information.

See Also

DateDaysToDate(), DateToDays()

DateTemplateToAscii Function ^TOP^

Purpose

Convert the specified date values into a string that is formatted according to a formatting template specification.

Declared In

DateTime.h

Prototype

UInt16 DateTemplateToAscii (
   const Char *templateP,
   UInt8 months,
   UInt8 days,
   UInt16 years,
   Char *stringP,
   Int16 stringLen
)

Parameters

templateP
A pointer to the template string used to format the date.
See the Comments section below for details on how to specify date formatting in this template string.
months
The month number, which must be a value between 1 and 12.
days
The day number, which must be a value between 1 and 31.
years
The four-digit year number. For example, 1995.
stringP
A pointer to a string that is updated with the result.
If stringP is NULL, this function does not write an output string; however, it does return the length required for the output string.
If stringP is not NULL, this function writes the formatted string to stringP, writing up to stringSize bytes into stringP.
stringLen
The size of the stringP buffer.

Returns

The length of the formatted string, without the terminating null byte.

The DateTemplateToAscii returns the required length of the formatted string even if the stringP parameter is NULL; this allows you to determine the buffer size at runtime.

Comments

This function is intended as a replacement for the DateToAscii() and DateToDOWDMFormat() functions.

This function uses the formatting template referenced by templateP to create a formatted string from the date values that you pass in.

You specify a series of formatting substrings in templateP. Each substring has the form:


^<valueType><formatModifier> 

Each substring has three components:

  • The ^ character begins a substring.
  • The <valueType> component is a single-digit value that specifies the value type.
  • The <formatModifier> component is a single-letter value that specifies how you want that value formatted.

The following is an example of a template specification with three substrings:

^0z ^2l ^4r

Table 57.1 shows the values you can specify for the <valueType> component. Note that the formatted result depends on the <modifier> value.

Table 57.1  Template value types for the DateTemplateToAscii function

Value

Value type

Formatted examples

0

Day number

1, 01, 23, 31

1

Day name

Tue, Tuesday

2

Month name

May, Aug, August

3

Month number

4, 04, 11

4

Year number

97, 1997

Table 57.2 shows the values you can specify for the <modifier> component of each template substring.

Table 57.2  Template modifier types for the DateTemplateToAscii function

Modifier

Description

s

Formats the value in short form

r

Formats the value in regular form

l

Formats the value in long form

z

Adds a leading zero to the formatted numeric value

Finally, Table 57.3 shows examples of each value type formatted with each modifier type.

Table 57.3  Examples of formatted values

Value type

Raw value

s
(Short format)

r
(Regular format)

l
(Long format)

z
(Zero format)

0
(Day number)

2

2

2

2

02

1
(Day name)

2

T

Tue

Tuesday

n/a

2
(Month name)

11

N

Nov

November

n/a

3
(Month number)

11

11

11

11

11

4
(Year number)

2000

00

2000

2000

n/a

For example, calling DateTemplateToAscii as follows:


DateTemplateToAscii("^0z ^2l ^4r", 2, 7, 
2000, myStr, 20) 

Produces the following formatted string:

07 February 2000

Compatibility

Implemented only if 3.5 New Feature Set is present. To use this function in code intended to be run on earlier versions of Palm OS, link with the PalmOSGlue library and call DateGlueTemplateToAscii. For more information, see Chapter 80, "PalmOSGlue Library."

See Also

DateToAscii(), DateToDOWDMFormat()

DateToAscii Function ^TOP^

Purpose

Convert the passed date to a string using the format specified by the dateFormat parameter.

Declared In

DateTime.h

Prototype

void DateToAscii (
   UInt8months,
   UInt8days,
   UInt16years,
   DateFormatTypedateFormat,
   Char*pString
)

Parameters

months
The month number, which must be a value between 1 and 12.
days
The day number, which must be a value between 1 and 31.
years
The four-digit year number. For example, 1995.
dateFormat
Any DateFormatType format.
pString
A pointer to string that is updated with the result.
This string must be of length dateStringLength for short formats or longDateStrLength for medium or long formats. Note that these lengths do include the terminating null byte. For more information about required string lengths, see Time Manager Constants.

Returns

Returns nothing. The string reference by pString is updated with the formatted string.

Comments

If you are using a debug ROM, the string buffer is filled with either dateStringLength or longStrLength debugging bytes, depending on the value of the dateFormat parameter.

It is important to allocate enough space for your string buffer. Finding buffer overflow errors can be difficult when using a debug ROM. One common situation is when you pass a buffer that is too small from a form, for an element such as a label or title. Then, the buffer overflow can clobber objects that follow the form in memory. When a form element's location information is corrupted, it disappears from the display.

Note that you can use the DateTemplateToAscii() function instead of this function if the 3.5 feature set is present. You can call the DateTemplateToAscii() function with a NULL string buffer to predetermine the required size for your buffer.

See Also

TimeToAscii(), DateToDOWDMFormat(), DateTemplateToAscii()

DateToDays Function ^TOP^

Purpose

Convert the DateType structure to the number of days elapsed from January 1, 1904.

Declared In

DateTime.h

Prototype

UInt32 DateToDays (
   DateTypedate
)

Parameters

date
A DateType structure.

Returns

Returns the number of days elapsed from January 1, 1904 to the specified date.

See Also

DateDaysToDate()

DateToDOWDMFormat Function ^TOP^

Purpose

Convert a date to a formatted string using the format specified by the dateFormat parameter. The resultant string includes the name of the day of the week.

Declared In

DateTime.h

Prototype

void DateToDOWDMFormat (
   UInt8months,
   UInt8days,
   UInt16years,
   DateFormatTypedateFormat,
   Char*pString
)

Parameters

months
The month number, which must be a value between 1 and 12.
days
The day number, which must be a value between 1 and 31.
years
The four-digit year number. For example, 1995.
dateFormat
Any DateFormatType format.
pString
A pointer to a string that is updated with the result. The string must be of length dowDateStringLength for short formats or dowLongDateStrLength for medium or long date formats. See Time Manager Constants for string buffer lengths.

Returns

Returns nothing. The string referenced by pString is updated with the formatted string.

Comments

The values of some of the Time Manager Constants that specify the required string buffer lengths do change from time to time. You should always use the constants or verify the required lengths by checking the datetime.h file.

It is important to allocate enough space for your string buffer. Finding buffer overflow errors can be difficult when using a debug ROM. One common situation is when you pass a buffer that is too small from a form, for an element such as a label or title. Then, the buffer overflow can clobber objects that follow the form in memory. When a form element's location information is corrupted, it disappears from the display.

Note that you can use the DateTemplateToAscii() function instead of this function if the 3.5 feature set is present. You can call the DateTemplateToAscii() function with a NULL string buffer to predetermine the required size for your buffer.

Compatibility

On Palm OS 3.1 Japanese ROMs, this function contains a bug that prevented it from properly displaying 4-byte long day names. To prevent this bug from affecting your application, use DateGlueToDOWDMFormat in the PalmOSGlue library instead of calling this function directly. For more information, see Chapter 80, "PalmOSGlue Library."

See Also

DateToAscii(), DateTemplateToAscii()

DayOfMonth Function ^TOP^

Purpose

Return a value that represents the day of a month on which the specified date occurs. The value represents a quantity such as "First Monday" or "Third Friday" as is used for repeating appointments in the Datebook.

Declared In

DateTime.h

Prototype

Int16 DayOfMonth (
   Int16month,
   Int16day,
   Int16year
)

Parameters

month
The month number, which must be a value between 1 and 12.
day
The day number, which must be a value between 1 and 31.
year
The four-digit year number. For example, 1995.

Returns

Returns a value that represents day of the month. This value is one of the DayOfMonthType values.

Comments

The returns value can be used to specify on which day of the month an appointment repeats.

DayOfWeek Function ^TOP^

Purpose

Return the day of the week value for a specified date.

Declared In

DateTime.h

Prototype

Int16 DayOfWeek (
   Int16month,
   Int16day,
   Int16year
)

Parameters

month
The month number, which must be a value between 1 and 12.
day
The day number, which must be a value between 1 and 31.
year
The four-digit year number. For example, 1995.

Returns

Returns one of the following values for the day of the week of the specified date, as shown in the following table:

Day name

Returned day value

Sunday

0

Monday

1

Tuesday

2

Wednesday

3

Thursday

4

Friday

5

Saturday

6

DaysInMonth Function ^TOP^

Purpose

Return the number of days in the month.

Declared In

DateTime.h

Prototype

Int16 DaysInMonth (
   Int16month,
   Int16year
)

Parameters

month
The month number, which must be a value between 1 and 12.
year
The four-digit year number. For example, 1995.

Returns

Returns the number of days in the month for the specified year.

TimAdjust Function ^TOP^

Purpose

Return a new date, with the time adjusted by the specified number of seconds.

Declared In

DateTime.h

Prototype

void TimAdjust (
   DateTimeType*dateTimeP,
   Int32adjustment
)

Parameters

dateTimeP
A pointer to a DateType structure.
adjustment
The number of seconds by which to adjust the time.

Returns

Returns nothing. The structure referenced by dateTimeP is modified to contain the updated date and time.

Comments

This function advances the time by the specified number of seconds and takes care of any wraparound conditions.

See Also

DateAdjust()

TimDateTimeToSeconds Function ^TOP^

Purpose

Return the number of seconds elapsed from 12:00 A.M. on January 1, 1904 to the specified date and time.

Declared In

DateTime.h

Prototype

UInt32 TimDateTimeToSeconds (
   constDateTimeType*dateTimeP
)

Parameters

dateTimeP
A pointer to a DateTimeType structure.

Returns

The number of seconds elapsed from 12:00 A.M. on January 1, 1904 to the date referenced by dateTimeP.

See Also

TimSecondsToDateTime()

TimGetSeconds Function ^TOP^

Purpose

Return the current date and time of the device in seconds since 12:00 A.M. on January 1, 1904.

Declared In

TimeMgr.h

Prototype

UInt32 TimGetSeconds (
   void
)

Parameters

None.

Returns

The number of seconds elapsed from 12:00 A.M. on January 1, 1904 to the current date and time on the device.

See Also

TimSetSeconds()

TimGetTicks Function ^TOP^

Purpose

Return the tick count since the last reset. The tick count does not advance while the device is in sleep mode.

Declared In

TimeMgr.h

Prototype

UInt32 TimGetTicks (
   void
)

Parameters

None.

Returns

Returns the tick count.

Comments

You can call the SysTicksPerSecond() routine to determine the number of ticks per second.

See Also

SysTicksPerSecond()

TimSecondsToDateTime Function ^TOP^

Purpose

Converts a date specified as the number of seconds since January 1, 1904 to a DateTimeType structure.

Declared In

DateTime.h

Prototype

void TimSecondsToDateTime (
   UInt32seconds,
   DateTimeType*dateTimeP
)

Parameters

seconds
A date specified as the number of seconds elapsed from 12:00 A.M. on January 1, 1904 to the date
dateTimeP
A pointer to a DateTimeType structure that is updated with the date and time values.

Returns

Returns nothing. The structure referenced by dateTimeP is updated with the date and time computed for the number of seconds since 12:00 A.M. on January 1, 1904.

See Also

TimDateTimeToSeconds()

TimSetSeconds Function ^TOP^

Purpose

Set the clock of the device to the date and time passed as the number of seconds since 12:00 A.M. on January 1, 1904.

Declared In

TimeMgr.h

Prototype

void TimSetSeconds (
   UInt32seconds
)

Parameters

seconds
The number of seconds since 12:00 A.M. on January 1, 1904.

Returns

Returns nothing.

Comments

If the Notification Feature Set is present, this function broadcasts the sysNotifyTimeChangeEvent to all interested parties. See Chapter 43, "Notification Manager," for more information.

See Also

TimGetSeconds()

TimeToAscii Function ^TOP^

Purpose

Convert the time to a string that is formatted according to the specified timeFormat.

Declared In

DateTime.h

Prototype

void TimeToAscii (
   UInt8hours,
   UInt8minutes,
   TimeFormatTypetimeFormat,
   Char*pString
)

Parameters

hours
The number of hours. This must be a value between 0 and 23.
minutes
The number of minutes. This must be a value between 0 and 59.
timeFormat
The time format for the resultant string. This must be one of the TimeFormatType values.
pString
A pointer to a string that is updated with the resultant string. This string must be of length timeStringLength.
See Time Manager Constants for information on string buffer lengths.

Returns

Returns nothing. The string referenced by pString is updated with the formatted string.

Comments

If you are using a debug ROM in Palm OS 3.5, the string buffer is filled with timeStringLength debugging bytes.

It is important to allocate enough space for your string buffer. Finding buffer overflow errors can be difficult when using a debug ROM. One common situation is when you pass a buffer that is too small from a form, for an element such as a label or title. Then, the buffer overflow can clobber objects that follow the form in memory. When a form element's location information is corrupted, it disappears from the display.

See Also

DateToAscii()

TimeZoneToAscii Function ^TOP^

Purpose

Convert a time zone to a string.

Declared In

DateTime.h

Prototype

void TimeZoneToAscii (
   Int16timeZone,
   constLmLocaleType*localeP,
   Char*string
)

Parameters

timeZone
A pointer to the time zone, given as minutes east of Greenwich Mean Time (GMT).
localeP
A pointer to a locale (see LmLocaleType) that identifies the time zone country. You can use the constant lmAnyLanguage as the value for the language field of the structure pointed to by this parameter.
string
A pointer to a string in which to return the result. This string must be of length timeZoneStringLength.

Returns

Returns nothing.

Comments

This function returns a descriptive string for the specified time zone. This string identifies the time zone first by its country, such as "USA (Mountain)" or "Canada (Eastern)." If the function cannot find a time zone that matches the specified GMT offset and country, it returns a string containing the time zone as a numeric offset from the GMT (for example, "GMT+9:00").

Compatibility

Implemented only if 4.0 New Feature Set is present.

TimTimeZoneToUTC Function ^TOP^

Purpose

Converts a date and time from a given time zone to Universal Coordinated Time (UTC). UTC is also known as Greenwich Mean Time (GMT).

Declared In

DateTime.h

Prototype

UInt32 TimTimeZoneToUTC (
   UInt32seconds,
   Int16timeZone,
   Int16daylightSavingAdjustment
)

Parameters

seconds
The number of seconds since 12:00 A.M. on January 1, 1904.
timeZone
The time zone, given as the number of minutes east of UTC. For time zones west of UTC but before the international dateline, this is a negative number.
daylightSavingAdjustment
The number of minutes to add to the current time for daylight savings time in this time zone.

Returns

Returns the same time as seconds but in the Universal Coordinated Time. The value is still given as the number of seconds since 12:00 A.M. on January 1, 1904.

Comments

The returned value is not necessarily the time in Greenwich because Greenwich may be observing daylight saving time.

You can use this function to convert the local time to UTC. The time zone and the daylight savings adjustment are system preferences that can be retrieved using PrefGetPreference(). For example, the following code converts the current local time to UTC:


Int16 timeZone =  
PrefGetPreference(prefTimeZone); 
Int16 daylightSavingAdjustment =  
PrefGetPreference(  
prefDaylightSavingAdjustment); 
UInt32 utcTime =  
TimTimeZoneToUTC(TimGetSeconds(), timeZone,  
daylightSavingAdjustment); 

Compatibility

Implemented only if 4.0 New Feature Set is present.

See Also

TimUTCToTimeZone()

TimUTCToTimeZone Function ^TOP^

Purpose

Converts a date and time from Universal Coordinated Time (UTC) to the specified time zone. UTC is also known as Greenwich Mean Time (GMT).

Declared In

DateTime.h

Prototype

UInt32 TimUTCToTimeZone (
   UInt32seconds,
   Int16timeZone,
   Int16daylightSavingAdjustment
)

Parameters

seconds
The number of seconds since 12:00 A.M. on January 1, 1904 in UTC.
timeZone
The time zone, given as the number of minutes east of UTC. For time zones west of UTC before the international dateline, this is a negative number.
daylightSavingAdjustment
The number of minutes to add to the current time for daylight savings time in this time zone.

Returns

Returns the same time as seconds but in the specified time zone. The value is still given as the number of seconds since 12:00 A.M. on January 1, 1904.

Comments

The seconds value is not necessarily the time in Greenwich because Greenwich may be observing daylight saving time.

Compatibility

Implemented only if 4.0 New Feature Set is present.

See Also

TimTimeZoneToUTC()