Date: Date and Time Printing, Parsing and Manipulation

Files
file	gnc-date.h
	Date and Time handling routines.

Data Structures
struct	timespec64
	Use a 64-bit unsigned int timespec. More...

Macros
#define	MAX_DATE_LENGTH   34
#define	QOF_UTC_DATE_FORMAT   "%Y-%m-%dT%H:%M:%SZ"
	UTC date format string. More...
#define	DATE_FORMAT_FIRST   QOF_DATE_FORMAT_US
#define	DATE_FORMAT_LAST   QOF_DATE_FORMAT_UTC
#define	qof_date_format_get_format   qof_date_text_format_get_string

Typedefs
typedef gint64	time64
typedef struct timespec64	Timespec

Enumerations
enum	QofDateFormat {   QOF_DATE_FORMAT_US, QOF_DATE_FORMAT_UK, QOF_DATE_FORMAT_CE, QOF_DATE_FORMAT_ISO,   QOF_DATE_FORMAT_LOCALE, QOF_DATE_FORMAT_UTC, QOF_DATE_FORMAT_CUSTOM }
enum	QofDateCompletion { QOF_DATE_COMPLETION_THISYEAR, QOF_DATE_COMPLETION_SLIDING }
enum	GNCDateMonthFormat { GNCDATE_MONTH_NUMBER, GNCDATE_MONTH_ABBREV, GNCDATE_MONTH_NAME }

Functions
struct tm *	gnc_localtime (const time64 *secs)
	fill out a time struct from a 64-bit time value. More...
struct tm *	gnc_localtime_r (const time64 *secs, struct tm *time)
	fill out a time struct from a 64-bit time value adjusted for the current time zone. More...
struct tm *	gnc_gmtime (const time64 *secs)
	fill out a time struct from a 64-bit time value More...
time64	gnc_mktime (struct tm *time)
	calculate seconds from the epoch given a time struct More...
time64	gnc_timegm (struct tm *time)
	calculate seconds from the epoch given a time struct More...
gchar *	gnc_ctime (const time64 *secs)
	Return a string representation of a date from a 64-bit time value. More...
time64	gnc_time (time64 *tbuf)
	get the current local time More...
time64	gnc_time_utc (time64 *tbuf)
	get the current utc time More...
gdouble	gnc_difftime (const time64 secs1, const time64 secs2)
	Find the difference in seconds between two time values. More...
GDateTime *	gnc_g_date_time_new_from_unix_local (time64 time)
void	gnc_tm_free (struct tm *time)
	free a struct tm* created with gnc_localtime() or gnc_gmtime() More...
GDateTime *	gnc_g_date_time_new_from_timespec_local (Timespec tm)
	Create a GDateTime from a Timespec. More...
void	qof_date_completion_set (QofDateCompletion dc, int backmonths)
gchar	dateSeparator (void)

Variables
const char *	gnc_default_strftime_date_format

GValue
GType	timespec_get_type (void)
#define	GNC_TYPE_TIMESPEC   (timespec_get_type ())

String / DateFormat conversion.
const gchar *	gnc_date_dateformat_to_string (QofDateFormat format)
	The string->value versions return FALSE on success and TRUE on failure.
gboolean	gnc_date_string_to_dateformat (const gchar *format_string, QofDateFormat *format)
	Converts the date format to a printable string. More...
const gchar *	gnc_date_monthformat_to_string (GNCDateMonthFormat format)
gboolean	gnc_date_string_to_monthformat (const gchar *format_string, GNCDateMonthFormat *format)
	Converts the month format to a printable string. More...

Timespec functions
gboolean	timespec_equal (const Timespec *ta, const Timespec *tb)
gint	timespec_cmp (const Timespec *ta, const Timespec *tb)
Timespec	timespec_diff (const Timespec *ta, const Timespec *tb)
Timespec	timespec_abs (const Timespec *t)
Timespec	timespecCanonicalDayTime (Timespec t)
Timespec	timespec_now (void)
void	timespecFromTime64 (Timespec *ts, time64 t)
time64	timespecToTime64 (Timespec ts)
GDate *	gnc_g_date_new_today (void)
GDate	timespec_to_gdate (Timespec ts)
Timespec	gdate_to_timespec (GDate d)
Timespec	gnc_dmy2timespec (gint day, gint month, gint year)
Timespec	gnc_dmy2timespec_end (gint day, gint month, gint year)
Timespec	gnc_iso8601_to_timespec_gmt (const gchar *)
gchar *	gnc_timespec_to_iso8601_buff (Timespec ts, gchar *buff)
void	gnc_timespec2dmy (Timespec ts, gint *day, gint *month, gint *year)
glong	gnc_timezone (const struct tm *tm)

QofDateFormat functions
QofDateFormat	qof_date_format_get (void)
void	qof_date_format_set (QofDateFormat df)
const gchar *	qof_date_format_get_string (QofDateFormat df)
const gchar *	qof_date_text_format_get_string (QofDateFormat df)

Date Printing/Scanning functions
gsize	qof_strftime (gchar *buf, gsize max, const gchar *format, const struct tm *tm)
size_t	qof_print_date_dmy_buff (gchar *buff, size_t buflen, int day, int month, int year)
size_t	qof_print_date_buff (char *buff, size_t buflen, time64 secs)
size_t	qof_print_gdate (char *buf, size_t bufflen, const GDate *gd)
char *	qof_print_date (time64 secs)
const char *	gnc_print_date (Timespec ts)
size_t	qof_print_date_time_buff (char *buff, size_t len, time64 secs)
gboolean	qof_scan_date (const char *buff, int *day, int *month, int *year)

Date Start/End Adjustment routines
Given a time value, adjust it to be the beginning or end of that day.
time64	gnc_time64_get_day_start (time64 time_val)
time64	gnc_time64_get_day_end (time64 time_val)
int	gnc_date_get_last_mday (int month, int year)

Today's Date
void	gnc_tm_get_today_start (struct tm *tm)
void	gnc_tm_get_today_end (struct tm *tm)
time64	gnc_time64_get_today_start (void)
time64	gnc_time64_get_today_end (void)
char *	gnc_date_timestamp (void)
	Make a timestamp in YYYYMMDDHHMMSS format. More...
void	gnc_dow_abbrev (gchar *buf, int buf_len, int dow)
#define	MIN_BUF_LEN   10

Detailed Description

Utility functions to handle date and time (adjusting, getting the current date, printing the date and time, etc.)

Overall, this file is quite a mess. Note, however, that other applications, besides just GnuCash, use this file. In particular, GnoTime (gttr.sourcefore.net) uses this file, and this file is formally a part of QOF (qof.sourceforge.net).

An important note about time-keeping: The general goal of any program that works with numeric time values SHOULD BE to always stores and use UNIVERSAL TIME internally. Universal time is the 'one true time' that is independent of one's location on planet Earth. It is measured in seconds from midnight January 1, 1970 in localtime-Grenwich (GMT). If one wants to display the local time, then the display-print routine should make all final tweaks to print the local time. The local time must not be kept as a numeric value anywhere in the program. If one wants to parse a user's input string as if it were local time, then the output of the parse routine MUST BE universal time. A sane program must never ever store (to file or db) a time that is not Universal Time. Break these rules, and you will rue the day...

Warning

HACK ALERT – the scan and print routines should probably be moved to somewhere else. The engine really isn't involved with things like printing formats. This is needed mostly by the GUI and so on. If a file-io backend needs date handling, it should do it itself, instead of depending on the routines here.

(to be renamed qofdate.h in libqof2.)

Author

Copyright (C) 1997 Robin D. Clark rclar.nosp@m.k@cs.nosp@m..hmc..nosp@m.edu

Copyright (C) 1998-2001,2003 Linas Vepstas linas.nosp@m.@lin.nosp@m.as.or.nosp@m.g

Macro Definition Documentation

#define MAX_DATE_LENGTH   34

The maximum length of a string created by the date printers

Definition at line 106 of file gnc-date.h.

#define qof_date_format_get_format   qof_date_text_format_get_string

Deprecated:

qof_date_format_get_format has been replaced by qof_date_text_format_get_string

Definition at line 144 of file gnc-date.h.

#define QOF_UTC_DATE_FORMAT   "%Y-%m-%dT%H:%M:%SZ"

UTC date format string.

ConstantsTimezone independent, date and time inclusive, as used in the QSF backend. The T and Z characters are from xsd:dateTime format in coordinated universal time, UTC. You can reproduce the string from the GNU/Linux command line using the date utility: date -u +Y-m-dTH:M:SZ = 2004-12-12T23:39:11Z The datestring must be timezone independent and include all specified fields. Remember to use gmtime() NOT localtime()!

Definition at line 118 of file gnc-date.h.

Typedef Documentation

typedef gint64 time64

Many systems, including Microsoft Windows and BSD-derived Unixes like Darwin, are retaining the int-32 typedef for time_t. Since this stops working in 2038, we define our own:

Definition at line 83 of file gnc-date.h.

typedef struct timespec64 Timespec

The Timespec is just like the unix 'struct timespec' except that we use a 64-bit unsigned int to store the seconds. This should adequately cover dates in the distant future as well as the distant past, as long as they're not more than a couple dozen times the age of the universe Values of this type can range from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807.

Definition at line 93 of file gnc-date.h.

Enumeration Type Documentation

enum GNCDateMonthFormat

This is how to format the month, as a number, an abbreviated string, or the full name.

Definition at line 150 of file gnc-date.h.

{
    GNCDATE_MONTH_NUMBER,
    GNCDATE_MONTH_ABBREV,
    GNCDATE_MONTH_NAME
} GNCDateMonthFormat;

enum QofDateCompletion

Enum for date completion modes (for dates entered without year)

Enumerator
QOF_DATE_COMPLETION_THISYEAR	use current year
QOF_DATE_COMPLETION_SLIDING	use sliding 12-month window

Definition at line 136 of file gnc-date.h.

{
    QOF_DATE_COMPLETION_THISYEAR, 
    QOF_DATE_COMPLETION_SLIDING,  
} QofDateCompletion;

enum QofDateFormat

Enum for determining a date format

Enumerator
QOF_DATE_FORMAT_US	United states: mm/dd/yyyy
QOF_DATE_FORMAT_UK	Britain: dd/mm/yyyy
QOF_DATE_FORMAT_CE	Continental Europe: dd.mm.yyyy
QOF_DATE_FORMAT_ISO	ISO: yyyy-mm-dd
QOF_DATE_FORMAT_LOCALE	Take from locale information
QOF_DATE_FORMAT_UTC	UTC: 2004-12-12T23:39:11Z
QOF_DATE_FORMAT_CUSTOM	Used by the check printing code

Definition at line 121 of file gnc-date.h.

{
    QOF_DATE_FORMAT_US,       
    QOF_DATE_FORMAT_UK,       
    QOF_DATE_FORMAT_CE,       
    QOF_DATE_FORMAT_ISO,      
    QOF_DATE_FORMAT_LOCALE,   
    QOF_DATE_FORMAT_UTC,      
    QOF_DATE_FORMAT_CUSTOM    
} QofDateFormat;

Function Documentation

gchar dateSeparator

(

void

)

dateSeparator Return the field separator for the current date format

Args: none

Return: date character

Globals: global dateFormat value

Timespec gdate_to_timespec

(

GDate

d

)

Turns a GDate into a Timespec, returning the first second of the day

gchar* gnc_ctime

(

const time64 *

secs

)

Return a string representation of a date from a 64-bit time value.

Parameters

secs	Seconds since 00:00:01 UTC 01 January 1970 (negative values are seconds before that moment)

Returns

A string, which must be freed with g_free(), representing the date in the following format: Thu Nov 24 18:22:48 1986
\0 This is equivalent to the strftime format a b H:M:S Y.

int gnc_date_get_last_mday	(	int	month,
		int	year
	)

Get the numerical last date of the month. (28, 29, 30, 31)

gboolean gnc_date_string_to_dateformat	(	const gchar *	format_string,
		QofDateFormat *	format
	)

Converts the date format to a printable string.

Note the reversed return values!

Returns

FALSE on success, TRUE on failure.

gboolean gnc_date_string_to_monthformat	(	const gchar *	format_string,
		GNCDateMonthFormat *	format
	)

Converts the month format to a printable string.

Note the reversed return values!

Returns

FALSE on success, TRUE on failure.

char* gnc_date_timestamp

(

void

)

Make a timestamp in YYYYMMDDHHMMSS format.

Returns

A pointer to the generated string.

Note

The caller owns this buffer and must g_free it when done.

gdouble gnc_difftime	(	const time64	secs1,
		const time64	secs2
	)

Find the difference in seconds between two time values.

Parameters

secs1	The first time value, in Seconds since 00:00:01 UTC 01 January 1970 (negative values are seconds before that moment)
secs2	The second time value, in Seconds since 00:00:01 UTC 01 January 1970 (negative values are seconds before that moment)

Returns

The difference in seconds between secs1 and secs2. If secs2 is later than secs1 the value will be negative.

Timespec gnc_dmy2timespec	(	gint	day,
		gint	month,
		gint	year
	)

Convert a day, month, and year to a Timespec, returning the first second of the day

Timespec gnc_dmy2timespec_end	(	gint	day,
		gint	month,
		gint	year
	)

Same as gnc_dmy2timespec, but last second of the day

void gnc_dow_abbrev	(	gchar *	buf,
		int	buf_len,
		int	dow
	)

Localized DOW abbreviation.

Parameters

buf_len	at least MIN_BUF_LEN
dow	struct tm semantics: 0=sunday .. 6=saturday

GDate* gnc_g_date_new_today

(

void

)

Returns a newly allocated date of the current clock time, taken from time(2). The caller must g_date_free() the object afterwards.

GDateTime* gnc_g_date_time_new_from_timespec_local

(

Timespec

tm

)

Create a GDateTime from a Timespec.

Parameters

ts	A local (int64-based) Timespec

Note

: GDateTimes use microseconds, not nanoseconds, so in theory we lose precision. In practice, there's no portable way to get either.

: Works around the lack of Win32 support in GTimeZone before GLib 2.36.

Returns

A GDateTime pointer. Free it with g_date_time_unref () when you're done with it.

GDateTime* gnc_g_date_time_new_from_unix_local

(

time64

time

)

Wrapper for g_date_time_new_from_unix_local() that takes special care on windows to take the local timezone into account. On unix, it just calles the g_date function.

struct tm* gnc_gmtime

(

const time64 *

secs

)

fill out a time struct from a 64-bit time value

Parameters

secs	Seconds since 00:00:01 UTC 01 January 1970 (negative values are seconds before that moment)

Returns

A struct tm*, allocated on the heap. Must be freed with gnc_tm_free() The time is UTC.

Timespec gnc_iso8601_to_timespec_gmt

(

const gchar *

)

The gnc_iso8601_to_timespec_gmt() routine converts an ISO-8601 style date/time string to Timespec. Please note that ISO-8601 strings are a representation of Universal Time (UTC), and as such, they 'store' UTC. To make them human readable, they show timezone information along with a local-time string. But fundamentally, they are UTC. Thus, thir routine takes a UTC input, and returns a UTC output.

For example: 1998-07-17 11:00:00.68-0500 is 680 milliseconds after 11 o'clock, central daylight time It is also 680 millisecs after 16:00:00 hours UTC.

Returns

The universl time.

XXX Caution: this routine does not handle strings that specify times before January 1 1970.

struct tm* gnc_localtime

(

const time64 *

secs

)

fill out a time struct from a 64-bit time value.

Parameters

secs	Seconds since 00:00:01 UTC 01 January 1970 (negative values are seconds before that moment).

Returns

A struct tm*, allocated on the heap. Must be freed with gnc_tm_free(). The time is adjusted for the current local time zone.

struct tm* gnc_localtime_r	(	const time64 *	secs,
		struct tm *	time
	)

fill out a time struct from a 64-bit time value adjusted for the current time zone.

Parameters

secs	Seconds since 00:00:01 UTC 01 January 1970 (negative values are seconds before that moment)
time	A struct tm* for the function to fill. The time is adjusted for the current local time zone.

time64 gnc_mktime

(

struct tm *

time

)

calculate seconds from the epoch given a time struct

Parameters

time	A struct tm* for the function to fill. The time is understood to be in the current local time zone.

Returns

Seconds since 00:00:01 UTC 01 January 1970 (negative values are seconds before that moment).

const char* gnc_print_date

(

Timespec

ts

)

Convenience; calls through to qof_print_date_dmy_buff(). Return: static global string.

Warning

This routine is not thread-safe, because it uses a single global buffer to store the return value. Use qof_print_date_buff() or qof_print_date() instead.

time64 gnc_time

(

time64 *

tbuf

)

get the current local time

Parameters

A	time64* which, if not NULL, will be filled in with the same value as is returned.

Returns

Seconds since 00:00:01 UTC 01 January 1970 (negative values are seconds before that moment)

time64 gnc_time64_get_day_end

(

time64

time_val

)

The gnc_time64_get_day_end() routine will take the given time in seconds and adjust it to the last second of that day.

time64 gnc_time64_get_day_start

(

time64

time_val

)

The gnc_time64_get_day_start() routine will take the given time in seconds and adjust it to the last second of that day.

time64 gnc_time64_get_today_end

(

void

)

The gnc_time64_get_today_end() routine returns a time64 value corresponding to the last second of today.

time64 gnc_time64_get_today_start

(

void

)

The gnc_time64_get_today_start() routine returns a time64 value corresponding to the first second of today.

time64 gnc_time_utc

(

time64 *

tbuf

)

get the current utc time

Parameters

A	time64* which, if not NULL, will be filled in with the same value as is returned.

Returns

Seconds since 00:00:01 UTC 01 January 1970 (negative values are seconds before that moment)

time64 gnc_timegm

(

struct tm *

time

)

calculate seconds from the epoch given a time struct

Parameters

time	A struct tm* for the function to fill. The time is understood to be utc.

Returns

Seconds since 00:00:01 UTC 01 January 1970 (negative values are seconds before that moment).

void gnc_timespec2dmy	(	Timespec	ts,
		gint *	day,
		gint *	month,
		gint *	year
	)

Set the proleptic Gregorian day, month, and year from a Timespec

Parameters

ts	input timespec
day	output day, 1 - 31
month	output month, 1 - 12
year	output year, 0001 - 9999 CE

gchar* gnc_timespec_to_iso8601_buff	(	Timespec	ts,
		gchar *	buff
	)

The gnc_timespec_to_iso8601_buff() routine takes the input UTC Timespec value and prints it as an ISO-8601 style string. The buffer must be long enough to contain the NULL-terminated string (32 characters + NUL). This routine returns a pointer to the null terminator (and can thus be used in the 'stpcpy' metaphor of string concatenation).

Please note that ISO-8601 strings are a representation of Universal Time (UTC), and as such, they 'store' UTC. To make them human readable, they show timezone information along with a local-time string. But fundamentally, they are UTC. Thus, this routine takes a UTC input, and returns a UTC output.

The string generated by this routine uses the local timezone on the machine on which it is executing to create the timestring.

glong gnc_timezone

(

const struct tm *

tm

)

The gnc_timezone function returns the number of seconds west of UTC represented by the tm argument, adjusted for daylight savings time.

This function requires a tm argument returned by localtime or set by mktime. This is a strange function! It requires that localtime or mktime be called before use. Subsequent calls to localtime or mktime may invalidate the result! The actual contents of tm may be used for both timezone offset and daylight savings time, or only daylight savings time! Timezone stuff under unix is not standardized and is a big mess.

void gnc_tm_free

(

struct tm *

time

)

free a struct tm* created with gnc_localtime() or gnc_gmtime()

Parameters

time	The struct tm* to be freed.

void gnc_tm_get_today_end

(

struct tm *

tm

)

The gnc_tm_get_today_end() routine takes a pointer to a struct tm and fills it in with the last second of the today.

void gnc_tm_get_today_start

(

struct tm *

tm

)

The gnc_tm_get_today_start() routine takes a pointer to a struct tm and fills it in with the first second of the today.

void qof_date_completion_set	(	QofDateCompletion	dc,
		int	backmonths
	)

The qof_date_completion_set() routing sets the date completion method to one of QOF_DATE_COMPLETION_THISYEAR (for completing the year to the current calendar year) or QOF_DATE_COMPLETION_SLIDING (for using a sliding 12-month window). The sliding window starts 'backmonth' months before the current month (0-11)

QofDateFormat qof_date_format_get

(

void

)

The qof_date_format_get routine returns the date format that the date printing will use when printing a date, and the scaning routines will assume when parsing a date.

Returns

: the one of the enumerated date formats.

const gchar* qof_date_format_get_string

(

QofDateFormat

df

)

This function returns a strftime formatting string for printing an all numeric date (e.g. 2005-09-14). The string returned is based upon the location specified.

Parameters

df	The date style (us, uk, iso, etc) that should be provided.

Returns

A formatting string that will print a date in the requested style

void qof_date_format_set

(

QofDateFormat

df

)

The qof_date_format_set() routine sets date format to one of US, UK, CE, OR ISO. Checks to make sure it's a legal value. Args: QofDateFormat: enumeration indicating preferred format

const gchar* qof_date_text_format_get_string

(

QofDateFormat

df

)

This function returns a strftime formatting string for printing a date using words and numbers (e.g. 2005-September-14). The string returned is based upon the location specified.

Parameters

df	The date style (us, uk, iso, etc) that should be provided.

Returns

A formatting string that will print a date in the requested style

char* qof_print_date

(

time64

secs

)

Convenience; calls through to qof_print_date_dmy_buff(). Return: string, which should be freed when no longer needed.

size_t qof_print_date_buff	(	char *	buff,
		size_t	buflen,
		time64	secs
	)

Convenience: calls through to qof_print_date_dmy_buff().

size_t qof_print_date_dmy_buff	(	gchar *	buff,
		size_t	buflen,
		int	day,
		int	month,
		int	year
	)

qof_print_date_dmy_buff Convert a date as day / month / year integers into a localized string representation

Args: buff - pointer to previously allocated character array; its size must be at lease MAX_DATE_LENTH bytes. len - length of the buffer, in bytes. day - day of the month as 1 ... 31 month - month of the year as 1 ... 12 year - year (4-digit)

Returns: number of characters printed

Globals: global dateFormat value

size_t qof_print_date_time_buff	(	char *	buff,
		size_t	len,
		time64	secs
	)

Returns the number of bytes printed.

size_t qof_print_gdate	(	char *	buf,
		size_t	bufflen,
		const GDate *	gd
	)

Convenience; calls through to qof_print_date_dmy_buff().

gboolean qof_scan_date	(	const char *	buff,
		int *	day,
		int *	month,
		int *	year
	)

qof_scan_date Convert a string into day / month / year integers according to the current dateFormat value.

Args: buff - pointer to date string day - will store day of the month as 1 ... 31 month - will store month of the year as 1 ... 12 year - will store the year (4-digit)

Return: TRUE if the string seemed to be a valid date; else FALSE.

Globals: uses global dateFormat value to assist in parsing.

gsize qof_strftime	(	gchar *	buf,
		gsize	max,
		const gchar *	format,
		const struct tm *	tm
	)

Warning

HACK ALERT – the scan and print routines should probably be moved to somewhere else. The engine really isn't involved with things like printing formats. This is needed mostly by the GUI and so on. If a file-io thing needs date handling, it should do it itself, instead of depending on the routines here.qof_strftime calls qof_format_time to print a given time and afterwards tries to put the result into a buffer of fixed size.

Parameters

buf	A buffer.
max	The size of buf in bytes.
format	A format specification in UTF-8.
tm	A broken-down time.

Returns

The number of characters written, not include the null byte, if the complete string, including the null byte, fits into the buffer. Otherwise 0.

Timespec timespec_abs

(

const Timespec *

t

)

absolute value, also normalised

gint timespec_cmp	(	const Timespec *	ta,
		const Timespec *	tb
	)

comparison: if (ta < tb) -1; else if (ta > tb) 1; else 0;

Timespec timespec_diff	(	const Timespec *	ta,
		const Timespec *	tb
	)

difference between ta and tb, results are normalised ie tv_sec and tv_nsec of the result have the same size abs(result.tv_nsec) <= 1000000000

gboolean timespec_equal	(	const Timespec *	ta,
		const Timespec *	tb
	)

strict equality

Timespec timespec_now

(

void

)

Returns the current clock time as a Timespec, taken from time(2).

GDate timespec_to_gdate

(

Timespec

ts

)

Turns a Timespec into a GDate

Timespec timespecCanonicalDayTime

(

Timespec

t

)

convert a timepair on a certain day (localtime) to the timepair representing midday on that day. Watch out - this is not the first second of the day, which is returned by various other functions returning a Timespec.

void timespecFromTime64	(	Timespec *	ts,
		time64	t
	)

Turns a time64 into a Timespec

time64 timespecToTime64

(

Timespec

ts

)

Turns a Timespec into a time64

Variable Documentation

const char* gnc_default_strftime_date_format

The default date format for use with strftime.