GDateTime

GDateTime — A structure representing Date and Time

Synopsis

#include <glib.h>

typedef             GTimeSpan;
#define             G_TIME_SPAN_DAY
#define             G_TIME_SPAN_HOUR
#define             G_TIME_SPAN_MINUTE
#define             G_TIME_SPAN_SECOND
#define             G_TIME_SPAN_MILLISECOND

                    GDateTime;
void                g_date_time_unref                   (GDateTime *datetime);
GDateTime *              g_date_time_ref                (GDateTime *datetime);

GDateTime *              g_date_time_new_now            (GTimeZone *tz);
GDateTime *              g_date_time_new_now_local      (void);
GDateTime *              g_date_time_new_now_utc        (void);

GDateTime *              g_date_time_new_from_unix_local
                                                        (gint64 t);
GDateTime *              g_date_time_new_from_unix_utc  (gint64 t);

GDateTime *              g_date_time_new_from_timeval_local
                                                        (const GTimeVal *tv);
GDateTime *              g_date_time_new_from_timeval_utc
                                                        (const GTimeVal *tv);

GDateTime *              g_date_time_new                (GTimeZone *tz,
                                                         gint year,
                                                         gint month,
                                                         gint day,
                                                         gint hour,
                                                         gint minute,
                                                         gdouble seconds);
GDateTime *              g_date_time_new_local          (gint year,
                                                         gint month,
                                                         gint day,
                                                         gint hour,
                                                         gint minute,
                                                         gdouble seconds);
GDateTime *              g_date_time_new_utc            (gint year,
                                                         gint month,
                                                         gint day,
                                                         gint hour,
                                                         gint minute,
                                                         gdouble seconds);

GDateTime *              g_date_time_add                (GDateTime *datetime,
                                                         GTimeSpan timespan);

GDateTime *              g_date_time_add_years          (GDateTime *datetime,
                                                         gint years);
GDateTime *              g_date_time_add_months         (GDateTime *datetime,
                                                         gint months);
GDateTime *              g_date_time_add_weeks          (GDateTime *datetime,
                                                         gint weeks);
GDateTime *              g_date_time_add_days           (GDateTime *datetime,
                                                         gint days);

GDateTime *              g_date_time_add_hours          (GDateTime *datetime,
                                                         gint hours);
GDateTime *              g_date_time_add_minutes        (GDateTime *datetime,
                                                         gint minutes);
GDateTime *              g_date_time_add_seconds        (GDateTime *datetime,
                                                         gdouble seconds);

GDateTime *              g_date_time_add_full           (GDateTime *datetime,
                                                         gint years,
                                                         gint months,
                                                         gint days,
                                                         gint hours,
                                                         gint minutes,
                                                         gdouble seconds);

gint                g_date_time_compare                 (gconstpointer dt1,
                                                         gconstpointer dt2);
GTimeSpan           g_date_time_difference              (GDateTime *end,
                                                         GDateTime *begin);
guint               g_date_time_hash                    (gconstpointer datetime);
gboolean            g_date_time_equal                   (gconstpointer dt1,
                                                         gconstpointer dt2);

void                g_date_time_get_ymd                 (GDateTime *datetime,
                                                         gint *year,
                                                         gint *month,
                                                         gint *day);

gint                g_date_time_get_year                (GDateTime *datetime);
gint                g_date_time_get_month               (GDateTime *datetime);
gint                g_date_time_get_day_of_month        (GDateTime *datetime);

gint                g_date_time_get_week_numbering_year (GDateTime *datetime);
gint                g_date_time_get_week_of_year        (GDateTime *datetime);
gint                g_date_time_get_day_of_week         (GDateTime *datetime);

gint                g_date_time_get_day_of_year         (GDateTime *datetime);

gint                g_date_time_get_hour                (GDateTime *datetime);
gint                g_date_time_get_minute              (GDateTime *datetime);
gint                g_date_time_get_second              (GDateTime *datetime);
gint                g_date_time_get_microsecond         (GDateTime *datetime);
gdouble             g_date_time_get_seconds             (GDateTime *datetime);

gint64              g_date_time_to_unix                 (GDateTime *datetime);
gboolean            g_date_time_to_timeval              (GDateTime *datetime,
                                                         GTimeVal *tv);

GTimeSpan           g_date_time_get_utc_offset          (GDateTime *datetime);
const gchar *            g_date_time_get_timezone_abbreviation
                                                        (GDateTime *datetime);
gboolean            g_date_time_is_daylight_savings     (GDateTime *datetime);

GDateTime *              g_date_time_to_timezone        (GDateTime *datetime,
                                                         GTimeZone *tz);
GDateTime *              g_date_time_to_local           (GDateTime *datetime);
GDateTime *              g_date_time_to_utc             (GDateTime *datetime);

gchar *                  g_date_time_format             (GDateTime *datetime,
                                                         const gchar *format);

Description

GDateTime is a structure that combines a Gregorian date and time into a single structure. It provides many conversion and methods to manipulate dates and times. Time precision is provided down to microseconds and the time can range (proleptically) from 0001-01-01 00:00:00 to 9999-12-31 23:59:59.999999. GDateTime follows POSIX time in the sense that it is oblivious to leap seconds.

GDateTime is an immutable object; once it has been created it cannot be modified further. All modifiers will create a new GDateTime. Nearly all such functions can fail due to the date or time going out of range, in which case NULL will be returned.

GDateTime is reference counted: the reference count is increased by calling g_date_time_ref() and decreased by calling g_date_time_unref(). When the reference count drops to 0, the resources allocated by the GDateTime structure are released.

Many parts of the API may produce non-obvious results. As an example, adding two months to January 31st will yield March 31st whereas adding one month and then one month again will yield either March 28th or March 29th. Also note that adding 24 hours is not always the same as adding one day (since days containing daylight savings time transitions are either 23 or 25 hours in length).

GDateTime is available since GLib 2.26.

Details

GTimeSpan

typedef gint64 GTimeSpan;

A value representing an interval of time, in microseconds.

Since 2.26


G_TIME_SPAN_DAY

#define G_TIME_SPAN_DAY                 (G_GINT64_CONSTANT (86400000000))

Evaluates to a time span of one day.

Since 2.26


G_TIME_SPAN_HOUR

#define G_TIME_SPAN_HOUR                (G_GINT64_CONSTANT (3600000000))

Evaluates to a time span of one hour.

Since 2.26


G_TIME_SPAN_MINUTE

#define G_TIME_SPAN_MINUTE              (G_GINT64_CONSTANT (60000000))

Evaluates to a time span of one minute.

Since 2.26


G_TIME_SPAN_SECOND

#define G_TIME_SPAN_SECOND              (G_GINT64_CONSTANT (1000000))

Evaluates to a time span of one second.

Since 2.26


G_TIME_SPAN_MILLISECOND

#define G_TIME_SPAN_MILLISECOND         (G_GINT64_CONSTANT (1000))

Evaluates to a time span of one millisecond.

Since 2.26


GDateTime

typedef struct _GDateTime GDateTime;

GDateTime is an opaque structure whose members cannot be accessed directly.

Since 2.26


g_date_time_unref ()

void                g_date_time_unref                   (GDateTime *datetime);

Atomically decrements the reference count of datetime by one.

When the reference count reaches zero, the resources allocated by datetime are freed

datetime :

a GDateTime

Since 2.26


g_date_time_ref ()

GDateTime *              g_date_time_ref                (GDateTime *datetime);

Atomically increments the reference count of datetime by one.

datetime :

a GDateTime

Returns :

the GDateTime with the reference count increased

Since 2.26


g_date_time_new_now ()

GDateTime *              g_date_time_new_now            (GTimeZone *tz);

Creates a GDateTime corresponding to this exact instant in the given time zone tz. The time is as accurate as the system allows, to a maximum accuracy of 1 microsecond.

This function will always succeed unless the system clock is set to truly insane values (or unless GLib is still being used after the year 9999).

You should release the return value by calling g_date_time_unref() when you are done with it.

tz :

a GTimeZone

Returns :

a new GDateTime, or NULL

Since 2.26


g_date_time_new_now_local ()

GDateTime *              g_date_time_new_now_local      (void);

Creates a GDateTime corresponding to this exact instant in the local time zone.

This is equivalent to calling g_date_time_new_now() with the time zone returned by g_time_zone_new_local().

Returns :

a new GDateTime, or NULL

Since 2.26


g_date_time_new_now_utc ()

GDateTime *              g_date_time_new_now_utc        (void);

Creates a GDateTime corresponding to this exact instant in UTC.

This is equivalent to calling g_date_time_new_now() with the time zone returned by g_time_zone_new_utc().

Returns :

a new GDateTime, or NULL

Since 2.26


g_date_time_new_from_unix_local ()

GDateTime *              g_date_time_new_from_unix_local
                                                        (gint64 t);

Creates a GDateTime corresponding to the given Unix time t in the local time zone.

Unix time is the number of seconds that have elapsed since 1970-01-01 00:00:00 UTC, regardless of the local time offset.

This call can fail (returning NULL) if t represents a time outside of the supported range of GDateTime.

You should release the return value by calling g_date_time_unref() when you are done with it.

t :

the Unix time

Returns :

a new GDateTime, or NULL

Since 2.26


g_date_time_new_from_unix_utc ()

GDateTime *              g_date_time_new_from_unix_utc  (gint64 t);

Creates a GDateTime corresponding to the given Unix time t in UTC.

Unix time is the number of seconds that have elapsed since 1970-01-01 00:00:00 UTC.

This call can fail (returning NULL) if t represents a time outside of the supported range of GDateTime.

You should release the return value by calling g_date_time_unref() when you are done with it.

t :

the Unix time

Returns :

a new GDateTime, or NULL

Since 2.26


g_date_time_new_from_timeval_local ()

GDateTime *              g_date_time_new_from_timeval_local
                                                        (const GTimeVal *tv);

Creates a GDateTime corresponding to the given GTimeVal tv in the local time zone.

The time contained in a GTimeVal is always stored in the form of seconds elapsed since 1970-01-01 00:00:00 UTC, regardless of the local time offset.

This call can fail (returning NULL) if tv represents a time outside of the supported range of GDateTime.

You should release the return value by calling g_date_time_unref() when you are done with it.

tv :

a GTimeVal

Returns :

a new GDateTime, or NULL

Since 2.26


g_date_time_new_from_timeval_utc ()

GDateTime *              g_date_time_new_from_timeval_utc
                                                        (const GTimeVal *tv);

Creates a GDateTime corresponding to the given GTimeVal tv in UTC.

The time contained in a GTimeVal is always stored in the form of seconds elapsed since 1970-01-01 00:00:00 UTC.

This call can fail (returning NULL) if tv represents a time outside of the supported range of GDateTime.

You should release the return value by calling g_date_time_unref() when you are done with it.

tv :

a GTimeVal

Returns :

a new GDateTime, or NULL

Since 2.26


g_date_time_new ()

GDateTime *              g_date_time_new                (GTimeZone *tz,
                                                         gint year,
                                                         gint month,
                                                         gint day,
                                                         gint hour,
                                                         gint minute,
                                                         gdouble seconds);

Creates a new GDateTime corresponding to the given date and time in the time zone tz.

The year must be between 1 and 9999, month between 1 and 12 and day between 1 and 28, 29, 30 or 31 depending on the month and the year.

hour must be between 0 and 23 and minute must be between 0 and 59.

seconds must be at least 0.0 and must be strictly less than 60.0. It will be rounded down to the nearest microsecond.

If the given time is not representable in the given time zone (for example, 02:30 on March 14th 2010 in Toronto, due to daylight savings time) then the time will be rounded up to the nearest existing time (in this case, 03:00). If this matters to you then you should verify the return value for containing the same as the numbers you gave.

In the case that the given time is ambiguous in the given time zone (for example, 01:30 on November 7th 2010 in Toronto, due to daylight savings time) then the time falling within standard (ie: non-daylight) time is taken.

It not considered a programmer error for the values to this function to be out of range, but in the case that they are, the function will return NULL.

You should release the return value by calling g_date_time_unref() when you are done with it.

tz :

a GTimeZone

year :

the year component of the date

month :

the month component of the date

day :

the day component of the date

hour :

the hour component of the date

minute :

the minute component of the date

seconds :

the number of seconds past the minute

Returns :

a new GDateTime, or NULL

Since 2.26


g_date_time_new_local ()

GDateTime *              g_date_time_new_local          (gint year,
                                                         gint month,
                                                         gint day,
                                                         gint hour,
                                                         gint minute,
                                                         gdouble seconds);

Creates a new GDateTime corresponding to the given date and time in the local time zone.

This call is equivalent to calling g_date_time_new() with the time zone returned by g_time_zone_new_local().

year :

the year component of the date

month :

the month component of the date

day :

the day component of the date

hour :

the hour component of the date

minute :

the minute component of the date

seconds :

the number of seconds past the minute

Returns :

a GDateTime, or NULL

Since 2.26.


g_date_time_new_utc ()

GDateTime *              g_date_time_new_utc            (gint year,
                                                         gint month,
                                                         gint day,
                                                         gint hour,
                                                         gint minute,
                                                         gdouble seconds);

Creates a new GDateTime corresponding to the given date and time in UTC.

This call is equivalent to calling g_date_time_new() with the time zone returned by g_time_zone_new_utc().

year :

the year component of the date

month :

the month component of the date

day :

the day component of the date

hour :

the hour component of the date

minute :

the minute component of the date

seconds :

the number of seconds past the minute

Returns :

a GDateTime, or NULL

Since 2.26.


g_date_time_add ()

GDateTime *              g_date_time_add                (GDateTime *datetime,
                                                         GTimeSpan timespan);

Creates a copy of datetime and adds the specified timespan to the copy.

datetime :

a GDateTime

timespan :

a GTimeSpan

Returns :

the newly created GDateTime which should be freed with g_date_time_unref().

Since 2.26


g_date_time_add_years ()

GDateTime *              g_date_time_add_years          (GDateTime *datetime,
                                                         gint years);

Creates a copy of datetime and adds the specified number of years to the copy.

datetime :

a GDateTime

years :

the number of years

Returns :

the newly created GDateTime which should be freed with g_date_time_unref().

Since 2.26


g_date_time_add_months ()

GDateTime *              g_date_time_add_months         (GDateTime *datetime,
                                                         gint months);

Creates a copy of datetime and adds the specified number of months to the copy.

datetime :

a GDateTime

months :

the number of months

Returns :

the newly created GDateTime which should be freed with g_date_time_unref().

Since 2.26


g_date_time_add_weeks ()

GDateTime *              g_date_time_add_weeks          (GDateTime *datetime,
                                                         gint weeks);

Creates a copy of datetime and adds the specified number of weeks to the copy.

datetime :

a GDateTime

weeks :

the number of weeks

Returns :

the newly created GDateTime which should be freed with g_date_time_unref().

Since 2.26


g_date_time_add_days ()

GDateTime *              g_date_time_add_days           (GDateTime *datetime,
                                                         gint days);

Creates a copy of datetime and adds the specified number of days to the copy.

datetime :

a GDateTime

days :

the number of days

Returns :

the newly created GDateTime which should be freed with g_date_time_unref().

Since 2.26


g_date_time_add_hours ()

GDateTime *              g_date_time_add_hours          (GDateTime *datetime,
                                                         gint hours);

Creates a copy of datetime and adds the specified number of hours

datetime :

a GDateTime

hours :

the number of hours to add

Returns :

the newly created GDateTime which should be freed with g_date_time_unref().

Since 2.26


g_date_time_add_minutes ()

GDateTime *              g_date_time_add_minutes        (GDateTime *datetime,
                                                         gint minutes);

Creates a copy of datetime adding the specified number of minutes.

datetime :

a GDateTime

minutes :

the number of minutes to add

Returns :

the newly created GDateTime which should be freed with g_date_time_unref().

Since 2.26


g_date_time_add_seconds ()

GDateTime *              g_date_time_add_seconds        (GDateTime *datetime,
                                                         gdouble seconds);

Creates a copy of datetime and adds the specified number of seconds.

datetime :

a GDateTime

seconds :

the number of seconds to add

Returns :

the newly created GDateTime which should be freed with g_date_time_unref().

Since 2.26


g_date_time_add_full ()

GDateTime *              g_date_time_add_full           (GDateTime *datetime,
                                                         gint years,
                                                         gint months,
                                                         gint days,
                                                         gint hours,
                                                         gint minutes,
                                                         gdouble seconds);

Creates a new GDateTime adding the specified values to the current date and time in datetime.

datetime :

a GDateTime

years :

the number of years to add

months :

the number of months to add

days :

the number of days to add

hours :

the number of hours to add

minutes :

the number of minutes to add

seconds :

the number of seconds to add

Returns :

the newly created GDateTime that should be freed with g_date_time_unref().

Since 2.26


g_date_time_compare ()

gint                g_date_time_compare                 (gconstpointer dt1,
                                                         gconstpointer dt2);

GCompareFunc-compatible comparison for GDateTime's. Both GDateTime<-- -->'s must be non-NULL.

dt1 :

first GDateTime to compare

dt2 :

second GDateTime to compare

Returns :

-1, 0 or 1 if dt1 is less than, equal to or greater than dt2.

Since 2.26


g_date_time_difference ()

GTimeSpan           g_date_time_difference              (GDateTime *end,
                                                         GDateTime *begin);

Calculates the difference in time between end and begin. The GTimeSpan that is returned is effectively end - begin (ie: positive if the first simparameter is larger).

end :

a GDateTime

begin :

a GDateTime

Returns :

the difference between the two GDateTime, as a time span expressed in microseconds.

Since 2.26


g_date_time_hash ()

guint               g_date_time_hash                    (gconstpointer datetime);

Hashes datetime into a guint, suitable for use within GHashTable.

datetime :

a GDateTime

Returns :

a guint containing the hash

Since 2.26


g_date_time_equal ()

gboolean            g_date_time_equal                   (gconstpointer dt1,
                                                         gconstpointer dt2);

Checks to see if dt1 and dt2 are equal.

Equal here means that they represent the same moment after converting them to the same time zone.

dt1 :

a GDateTime

dt2 :

a GDateTime

Returns :

TRUE if dt1 and dt2 are equal

Since 2.26


g_date_time_get_ymd ()

void                g_date_time_get_ymd                 (GDateTime *datetime,
                                                         gint *year,
                                                         gint *month,
                                                         gint *day);

Retrieves the Gregorian day, month, and year of a given GDateTime.

datetime :

a GDateTime.

year :

the return location for the gregorian year, or NULL. [out]

month :

the return location for the month of the year, or NULL. [out]

day :

the return location for the day of the month, or NULL. [out]

Since 2.26


g_date_time_get_year ()

gint                g_date_time_get_year                (GDateTime *datetime);

Retrieves the year represented by datetime in the Gregorian calendar.

datetime :

A GDateTime

Returns :

the year represented by datetime

Since 2.26


g_date_time_get_month ()

gint                g_date_time_get_month               (GDateTime *datetime);

Retrieves the month of the year represented by datetime in the Gregorian calendar.

datetime :

a GDateTime

Returns :

the month represented by datetime

Since 2.26


g_date_time_get_day_of_month ()

gint                g_date_time_get_day_of_month        (GDateTime *datetime);

Retrieves the day of the month represented by datetime in the gregorian calendar.

datetime :

a GDateTime

Returns :

the day of the month

Since 2.26


g_date_time_get_week_numbering_year ()

gint                g_date_time_get_week_numbering_year (GDateTime *datetime);

Returns the ISO 8601 week-numbering year in which the week containing datetime falls.

This function, taken together with g_date_time_get_week_of_year() and g_date_time_get_day_of_week() can be used to determine the full ISO week date on which datetime falls.

This is usually equal to the normal Gregorian year (as returned by g_date_time_get_year()), except as detailed below:

For Thursday, the week-numbering year is always equal to the usual calendar year. For other days, the number is such that every day within a complete week (Monday to Sunday) is contained within the same week-numbering year.

For Monday, Tuesday and Wednesday occuring near the end of the year, this may mean that the week-numbering year is one greater than the calendar year (so that these days have the same week-numbering year as the Thursday occuring early in the next year).

For Friday, Saturaday and Sunday occuring near the start of the year, this may mean that the week-numbering year is one less than the calendar year (so that these days have the same week-numbering year as the Thursday occuring late in the previous year).

An equivalent description is that the week-numbering year is equal to the calendar year containing the majority of the days in the current week (Monday to Sunday).

Note that January 1 0001 in the proleptic Gregorian calendar is a Monday, so this function never returns 0.

datetime :

a GDateTime

Returns :

the ISO 8601 week-numbering year for datetime

Since 2.26


g_date_time_get_week_of_year ()

gint                g_date_time_get_week_of_year        (GDateTime *datetime);

Returns the ISO 8601 week number for the week containing datetime. The ISO 8601 week number is the same for every day of the week (from Moday through Sunday). That can produce some unusual results (described below).

The first week of the year is week 1. This is the week that contains the first Thursday of the year. Equivalently, this is the first week that has more than 4 of its days falling within the calendar year.

The value 0 is never returned by this function. Days contained within a year but occuring before the first ISO 8601 week of that year are considered as being contained in the last week of the previous year. Similarly, the final days of a calendar year may be considered as being part of the first ISO 8601 week of the next year if 4 or more days of that week are contained within the new year.

datetime :

a GDateTime

Returns :

the ISO 8601 week number for datetime.

Since 2.26


g_date_time_get_day_of_week ()

gint                g_date_time_get_day_of_week         (GDateTime *datetime);

Retrieves the ISO 8601 day of the week on which datetime falls (1 is Monday, 2 is Tuesday... 7 is Sunday).

datetime :

a GDateTime

Returns :

the day of the week

Since 2.26


g_date_time_get_day_of_year ()

gint                g_date_time_get_day_of_year         (GDateTime *datetime);

Retrieves the day of the year represented by datetime in the Gregorian calendar.

datetime :

a GDateTime

Returns :

the day of the year

Since 2.26


g_date_time_get_hour ()

gint                g_date_time_get_hour                (GDateTime *datetime);

Retrieves the hour of the day represented by datetime

datetime :

a GDateTime

Returns :

the hour of the day

Since 2.26


g_date_time_get_minute ()

gint                g_date_time_get_minute              (GDateTime *datetime);

Retrieves the minute of the hour represented by datetime

datetime :

a GDateTime

Returns :

the minute of the hour

Since 2.26


g_date_time_get_second ()

gint                g_date_time_get_second              (GDateTime *datetime);

Retrieves the second of the minute represented by datetime

datetime :

a GDateTime

Returns :

the second represented by datetime

Since 2.26


g_date_time_get_microsecond ()

gint                g_date_time_get_microsecond         (GDateTime *datetime);

Retrieves the microsecond of the date represented by datetime

datetime :

a GDateTime

Returns :

the microsecond of the second

Since 2.26


g_date_time_get_seconds ()

gdouble             g_date_time_get_seconds             (GDateTime *datetime);

Retrieves the number of seconds since the start of the last minute, including the fractional part.

datetime :

a GDateTime

Returns :

the number of seconds

Since 2.26


g_date_time_to_unix ()

gint64              g_date_time_to_unix                 (GDateTime *datetime);

Gives the Unix time corresponding to datetime, rounding down to the nearest second.

Unix time is the number of seconds that have elapsed since 1970-01-01 00:00:00 UTC, regardless of the time zone associated with datetime.

datetime :

a GDateTime

Returns :

the Unix time corresponding to datetime

Since 2.26


g_date_time_to_timeval ()

gboolean            g_date_time_to_timeval              (GDateTime *datetime,
                                                         GTimeVal *tv);

Stores the instant in time that datetime represents into tv.

The time contained in a GTimeVal is always stored in the form of seconds elapsed since 1970-01-01 00:00:00 UTC, regardless of the time zone associated with datetime.

On systems where 'long' is 32bit (ie: all 32bit systems and all Windows systems), a GTimeVal is incapable of storing the entire range of values that GDateTime is capable of expressing. On those systems, this function returns FALSE to indicate that the time is out of range.

On systems where 'long' is 64bit, this function never fails.

datetime :

a GDateTime

tv :

a GTimeVal to modify

Returns :

TRUE if successful, else FALSE

Since 2.26


g_date_time_get_utc_offset ()

GTimeSpan           g_date_time_get_utc_offset          (GDateTime *datetime);

Determines the offset to UTC in effect at the time and in the time zone of datetime.

The offset is the number of microseconds that you add to UTC time to arrive at local time for the time zone (ie: negative numbers for time zones west of GMT, positive numbers for east).

If datetime represents UTC time, then the offset is always zero.

datetime :

a GDateTime

Returns :

the number of microseconds that should be added to UTC to get the local time

Since 2.26


g_date_time_get_timezone_abbreviation ()

const gchar *            g_date_time_get_timezone_abbreviation
                                                        (GDateTime *datetime);

Determines the time zone abbreviation to be used at the time and in the time zone of datetime.

For example, in Toronto this is currently "EST" during the winter months and "EDT" during the summer months when daylight savings time is in effect.

datetime :

a GDateTime

Returns :

the time zone abbreviation. The returned string is owned by the GDateTime and it should not be modified or freed. [transfer none]

Since 2.26


g_date_time_is_daylight_savings ()

gboolean            g_date_time_is_daylight_savings     (GDateTime *datetime);

Determines if daylight savings time is in effect at the time and in the time zone of datetime.

datetime :

a GDateTime

Returns :

TRUE if daylight savings time is in effect

Since 2.26


g_date_time_to_timezone ()

GDateTime *              g_date_time_to_timezone        (GDateTime *datetime,
                                                         GTimeZone *tz);

Create a new GDateTime corresponding to the same instant in time as datetime, but in the time zone tz.

This call can fail in the case that the time goes out of bounds. For example, converting 0001-01-01 00:00:00 UTC to a time zone west of Greenwich will fail (due to the year 0 being out of range).

You should release the return value by calling g_date_time_unref() when you are done with it.

datetime :

a GDateTime

tz :

the new GTimeZone

Returns :

a new GDateTime, or NULL

Since 2.26


g_date_time_to_local ()

GDateTime *              g_date_time_to_local           (GDateTime *datetime);

Creates a new GDateTime corresponding to the same instant in time as datetime, but in the local time zone.

This call is equivalent to calling g_date_time_to_timezone() with the time zone returned by g_time_zone_new_local().

datetime :

a GDateTime

Returns :

the newly created GDateTime

Since 2.26


g_date_time_to_utc ()

GDateTime *              g_date_time_to_utc             (GDateTime *datetime);

Creates a new GDateTime corresponding to the same instant in time as datetime, but in UTC.

This call is equivalent to calling g_date_time_to_timezone() with the time zone returned by g_time_zone_new_utc().

datetime :

a GDateTime

Returns :

the newly created GDateTime

Since 2.26


g_date_time_format ()

gchar *                  g_date_time_format             (GDateTime *datetime,
                                                         const gchar *format);

Creates a newly allocated string representing the requested format.

The following format specifiers are supported:

%a:

the abbreviated weekday name according to the current locale

%A:

the full weekday name according to the current locale

%b:

the abbreviated month name according to the current locale

%B:

the full month name according to the current locale

%d:

the day of the month as a decimal number (range 01 to 31)

%e:

the day of the month as a decimal number (range 1 to 31)

%F:

equivalent to %Y-%m-%d (the ISO 8601 date format)

%h:

equivalent to %b

%H:

the hour as a decimal number using a 24-hour clock (range 00 to 23)

%I:

the hour as a decimal number using a 12-hour clock (range 01 to 12)

%j:

the day of the year as a decimal number (range 001 to 366)

%k:

the hour (24-hour clock) as a decimal number (range 0 to 23); single digits are preceded by a blank

%l:

the hour (12-hour clock) as a decimal number (range 1 to 12); single digits are preceded by a blank

%m:

the month as a decimal number (range 01 to 12)

%M:

the minute as a decimal number (range 00 to 59)

%N:

the micro-seconds as a decimal number

%p:

either "AM" or "PM" according to the given time value, or the corresponding strings for the current locale. Noon is treated as "PM" and midnight as "AM".

%P:

like %p but lowercase: "am" or "pm" or a corresponding string for the current locale

%r:

the time in a.m. or p.m. notation

%R:

the time in 24-hour notation (%H:%M)

%s:

the number of seconds since the Epoch, that is, since 1970-01-01 00:00:00 UTC

%S:

the second as a decimal number (range 00 to 60)

%t:

a tab character

%u:

the day of the week as a decimal, range 1 to 7, Monday being 1

%W:

the week number of the current year as a decimal number

%x:

the preferred date representation for the current locale without the time

%X:

the preferred time representation for the current locale without the date

%y:

the year as a decimal number without the century

%Y:

the year as a decimal number including the century

%z:

the time-zone as hour offset from UTC

%Z:

the time zone or name or abbreviation

%%%:

a literal %% character

datetime :

A GDateTime

format :

a valid UTF-8 string, containing the format for the GDateTime

Returns :

a newly allocated string formatted to the requested format or NULL in the case that there was an error. The string should be freed with g_free().

Since 2.26

See Also

GTimeZone