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Date and Time Functions

Date and Time Functions — calendrical calculations and miscellaneous time stuff

Functions

void g_get_current_time ()
void g_usleep ()
void g_time_val_add ()
gboolean g_time_val_from_iso8601 ()
gchar * g_time_val_to_iso8601 ()
gint64 g_get_monotonic_time ()
gint64 g_get_real_time ()
GDate * g_date_new ()
GDate * g_date_new_dmy ()
GDate * g_date_new_julian ()
void g_date_clear ()
void g_date_free ()
void g_date_set_day ()
void g_date_set_month ()
void g_date_set_year ()
void g_date_set_dmy ()
void g_date_set_julian ()
void g_date_set_time ()
void g_date_set_time_t ()
void g_date_set_time_val ()
void g_date_set_parse ()
void g_date_add_days ()
void g_date_subtract_days ()
void g_date_add_months ()
void g_date_subtract_months ()
void g_date_add_years ()
void g_date_subtract_years ()
gint g_date_days_between ()
gint g_date_compare ()
void g_date_clamp ()
void g_date_order ()
GDateDay g_date_get_day ()
GDateMonth g_date_get_month ()
GDateYear g_date_get_year ()
guint32 g_date_get_julian ()
GDateWeekday g_date_get_weekday ()
guint g_date_get_day_of_year ()
guint8 g_date_get_days_in_month ()
gboolean g_date_is_first_of_month ()
gboolean g_date_is_last_of_month ()
gboolean g_date_is_leap_year ()
guint g_date_get_monday_week_of_year ()
guint8 g_date_get_monday_weeks_in_year ()
guint g_date_get_sunday_week_of_year ()
guint8 g_date_get_sunday_weeks_in_year ()
guint g_date_get_iso8601_week_of_year ()
gsize g_date_strftime ()
void g_date_to_struct_tm ()
gboolean g_date_valid ()
gboolean g_date_valid_day ()
gboolean g_date_valid_month ()
gboolean g_date_valid_year ()
gboolean g_date_valid_dmy ()
gboolean g_date_valid_julian ()
gboolean g_date_valid_weekday ()

Types and Values

#define G_USEC_PER_SEC
struct GTimeVal
struct GDate
typedef GTime
enum GDateDMY
typedef GDateDay
enum GDateMonth
typedef GDateYear
enum GDateWeekday
#define G_DATE_BAD_DAY
#define G_DATE_BAD_JULIAN
#define G_DATE_BAD_YEAR

Includes

#include <glib.h>

Description

The GDate data structure represents a day between January 1, Year 1, and sometime a few thousand years in the future (right now it will go to the year 65535 or so, but g_date_set_parse() only parses up to the year 8000 or so - just count on "a few thousand"). GDate is meant to represent everyday dates, not astronomical dates or historical dates or ISO timestamps or the like. It extrapolates the current Gregorian calendar forward and backward in time; there is no attempt to change the calendar to match time periods or locations. GDate does not store time information; it represents a day.

The GDate implementation has several nice features; it is only a 64-bit struct, so storing large numbers of dates is very efficient. It can keep both a Julian and day-month-year representation of the date, since some calculations are much easier with one representation or the other. A Julian representation is simply a count of days since some fixed day in the past; for GDate the fixed day is January 1, 1 AD. ("Julian" dates in the GDate API aren't really Julian dates in the technical sense; technically, Julian dates count from the start of the Julian period, Jan 1, 4713 BC).

GDate is simple to use. First you need a "blank" date; you can get a dynamically allocated date from g_date_new(), or you can declare an automatic variable or array and initialize it to a sane state by calling g_date_clear(). A cleared date is sane; it's safe to call g_date_set_dmy() and the other mutator functions to initialize the value of a cleared date. However, a cleared date is initially invalid, meaning that it doesn't represent a day that exists. It is undefined to call any of the date calculation routines on an invalid date. If you obtain a date from a user or other unpredictable source, you should check its validity with the g_date_valid() predicate. g_date_valid() is also used to check for errors with g_date_set_parse() and other functions that can fail. Dates can be invalidated by calling g_date_clear() again.

It is very important to use the API to access the GDate struct. Often only the day-month-year or only the Julian representation is valid. Sometimes neither is valid. Use the API.

GLib also features GDateTime which represents a precise time.

Functions

g_get_current_time ()

void
g_get_current_time (GTimeVal *result);

Equivalent to the UNIX gettimeofday() function, but portable.

You may find g_get_real_time() to be more convenient.

Parameters

result

GTimeVal structure in which to store current time.

 

g_usleep ()

void
g_usleep (gulong microseconds);

Pauses the current thread for the given number of microseconds.

There are 1 million microseconds per second (represented by the G_USEC_PER_SEC macro). g_usleep() may have limited precision, depending on hardware and operating system; don't rely on the exact length of the sleep.

Parameters

microseconds

number of microseconds to pause

 

g_time_val_add ()

void
g_time_val_add (GTimeVal *time_,
                glong microseconds);

Adds the given number of microseconds to time_ . microseconds can also be negative to decrease the value of time_ .

Parameters

time_

a GTimeVal

 

microseconds

number of microseconds to add to time

 

g_time_val_from_iso8601 ()

gboolean
g_time_val_from_iso8601 (const gchar *iso_date,
                         GTimeVal *time_);

Converts a string containing an ISO 8601 encoded date and time to a GTimeVal and puts it into time_ .

iso_date must include year, month, day, hours, minutes, and seconds. It can optionally include fractions of a second and a time zone indicator. (In the absence of any time zone indication, the timestamp is assumed to be in local time.)

Parameters

iso_date

an ISO 8601 encoded date string

 

time_

a GTimeVal.

[out]

Returns

TRUE if the conversion was successful.

Since: 2.12


g_time_val_to_iso8601 ()

gchar *
g_time_val_to_iso8601 (GTimeVal *time_);

Converts time_ into an RFC 3339 encoded string, relative to the Coordinated Universal Time (UTC). This is one of the many formats allowed by ISO 8601.

ISO 8601 allows a large number of date/time formats, with or without punctuation and optional elements. The format returned by this function is a complete date and time, with optional punctuation included, the UTC time zone represented as "Z", and the tv_usec part included if and only if it is nonzero, i.e. either "YYYY-MM-DDTHH:MM:SSZ" or "YYYY-MM-DDTHH:MM:SS.fffffZ".

This corresponds to the Internet date/time format defined by RFC 3339, and to either of the two most-precise formats defined by the W3C Note Date and Time Formats. Both of these documents are profiles of ISO 8601.

Use g_date_time_format() or g_strdup_printf() if a different variation of ISO 8601 format is required.

If time_ represents a date which is too large to fit into a struct tm, NULL will be returned. This is platform dependent, but it is safe to assume years up to 3000 are supported. The return value of g_time_val_to_iso8601() has been nullable since GLib 2.54; before then, GLib would crash under the same conditions.

Parameters

time_

a GTimeVal

 

Returns

a newly allocated string containing an ISO 8601 date, or NULL if time_ was too large.

[nullable]

Since: 2.12


g_get_monotonic_time ()

gint64
g_get_monotonic_time (void);

Queries the system monotonic time.

The monotonic clock will always increase and doesn't suffer discontinuities when the user (or NTP) changes the system time. It may or may not continue to tick during times where the machine is suspended.

We try to use the clock that corresponds as closely as possible to the passage of time as measured by system calls such as poll() but it may not always be possible to do this.

Returns

the monotonic time, in microseconds

Since: 2.28


g_get_real_time ()

gint64
g_get_real_time (void);

Queries the system wall-clock time.

This call is functionally equivalent to g_get_current_time() except that the return value is often more convenient than dealing with a GTimeVal.

You should only use this call if you are actually interested in the real wall-clock time. g_get_monotonic_time() is probably more useful for measuring intervals.

Returns

the number of microseconds since January 1, 1970 UTC.

Since: 2.28


g_date_new ()

GDate *
g_date_new (void);

Allocates a GDate and initializes it to a sane state. The new date will be cleared (as if you'd called g_date_clear()) but invalid (it won't represent an existing day). Free the return value with g_date_free().

Returns

a newly-allocated GDate


g_date_new_dmy ()

GDate *
g_date_new_dmy (GDateDay day,
                GDateMonth month,
                GDateYear year);

Like g_date_new(), but also sets the value of the date. Assuming the day-month-year triplet you pass in represents an existing day, the returned date will be valid.

Parameters

day

day of the month

 

month

month of the year

 

year

year

 

Returns

a newly-allocated GDate initialized with day , month , and year


g_date_new_julian ()

GDate *
g_date_new_julian (guint32 julian_day);

Like g_date_new(), but also sets the value of the date. Assuming the Julian day number you pass in is valid (greater than 0, less than an unreasonably large number), the returned date will be valid.

Parameters

julian_day

days since January 1, Year 1

 

Returns

a newly-allocated GDate initialized with julian_day


g_date_clear ()

void
g_date_clear (GDate *date,
              guint n_dates);

Initializes one or more GDate structs to a sane but invalid state. The cleared dates will not represent an existing date, but will not contain garbage. Useful to init a date declared on the stack. Validity can be tested with g_date_valid().

Parameters

date

pointer to one or more dates to clear

 

n_dates

number of dates to clear

 

g_date_free ()

void
g_date_free (GDate *date);

Frees a GDate returned from g_date_new().

Parameters

date

a GDate to free

 

g_date_set_day ()

void
g_date_set_day (GDate *date,
                GDateDay day);

Sets the day of the month for a GDate. If the resulting day-month-year triplet is invalid, the date will be invalid.

Parameters

date

a GDate

 

day

day to set

 

g_date_set_month ()

void
g_date_set_month (GDate *date,
                  GDateMonth month);

Sets the month of the year for a GDate. If the resulting day-month-year triplet is invalid, the date will be invalid.

Parameters

date

a GDate

 

month

month to set

 

g_date_set_year ()

void
g_date_set_year (GDate *date,
                 GDateYear year);

Sets the year for a GDate. If the resulting day-month-year triplet is invalid, the date will be invalid.

Parameters

date

a GDate

 

year

year to set

 

g_date_set_dmy ()

void
g_date_set_dmy (GDate *date,
                GDateDay day,
                GDateMonth month,
                GDateYear y);

Sets the value of a GDate from a day, month, and year. The day-month-year triplet must be valid; if you aren't sure it is, call g_date_valid_dmy() to check before you set it.

Parameters

date

a GDate

 

day

day

 

month

month

 

y

year

 

g_date_set_julian ()

void
g_date_set_julian (GDate *date,
                   guint32 julian_date);

Sets the value of a GDate from a Julian day number.

Parameters

date

a GDate

 

julian_date

Julian day number (days since January 1, Year 1)

 

g_date_set_time ()

void
g_date_set_time (GDate *date,
                 GTime time_);

g_date_set_time has been deprecated since version 2.10 and should not be used in newly-written code.

Use g_date_set_time_t() instead.

Sets the value of a date from a GTime value. The time to date conversion is done using the user's current timezone.

Parameters

date

a GDate.

 

time_

GTime value to set.

 

g_date_set_time_t ()

void
g_date_set_time_t (GDate *date,
                   time_t timet);

Sets the value of a date to the date corresponding to a time specified as a time_t. The time to date conversion is done using the user's current timezone.

To set the value of a date to the current day, you could write:

1
g_date_set_time_t (date, time (NULL));

Parameters

date

a GDate

 

timet

time_t value to set

 

Since: 2.10


g_date_set_time_val ()

void
g_date_set_time_val (GDate *date,
                     GTimeVal *timeval);

Sets the value of a date from a GTimeVal value. Note that the tv_usec member is ignored, because GDate can't make use of the additional precision.

The time to date conversion is done using the user's current timezone.

Parameters

date

a GDate

 

timeval

GTimeVal value to set

 

Since: 2.10


g_date_set_parse ()

void
g_date_set_parse (GDate *date,
                  const gchar *str);

Parses a user-inputted string str , and try to figure out what date it represents, taking the current locale into account. If the string is successfully parsed, the date will be valid after the call. Otherwise, it will be invalid. You should check using g_date_valid() to see whether the parsing succeeded.

This function is not appropriate for file formats and the like; it isn't very precise, and its exact behavior varies with the locale. It's intended to be a heuristic routine that guesses what the user means by a given string (and it does work pretty well in that capacity).

Parameters

date

a GDate to fill in

 

str

string to parse

 

g_date_add_days ()

void
g_date_add_days (GDate *date,
                 guint n_days);

Increments a date some number of days. To move forward by weeks, add weeks*7 days. The date must be valid.

Parameters

date

a GDate to increment

 

n_days

number of days to move the date forward

 

g_date_subtract_days ()

void
g_date_subtract_days (GDate *date,
                      guint n_days);

Moves a date some number of days into the past. To move by weeks, just move by weeks*7 days. The date must be valid.

Parameters

date

a GDate to decrement

 

n_days

number of days to move

 

g_date_add_months ()

void
g_date_add_months (GDate *date,
                   guint n_months);

Increments a date by some number of months. If the day of the month is greater than 28, this routine may change the day of the month (because the destination month may not have the current day in it). The date must be valid.

Parameters

date

a GDate to increment

 

n_months

number of months to move forward

 

g_date_subtract_months ()

void
g_date_subtract_months (GDate *date,
                        guint n_months);

Moves a date some number of months into the past. If the current day of the month doesn't exist in the destination month, the day of the month may change. The date must be valid.

Parameters

date

a GDate to decrement

 

n_months

number of months to move

 

g_date_add_years ()

void
g_date_add_years (GDate *date,
                  guint n_years);

Increments a date by some number of years. If the date is February 29, and the destination year is not a leap year, the date will be changed to February 28. The date must be valid.

Parameters

date

a GDate to increment

 

n_years

number of years to move forward

 

g_date_subtract_years ()

void
g_date_subtract_years (GDate *date,
                       guint n_years);

Moves a date some number of years into the past. If the current day doesn't exist in the destination year (i.e. it's February 29 and you move to a non-leap-year) then the day is changed to February 29. The date must be valid.

Parameters

date

a GDate to decrement

 

n_years

number of years to move

 

g_date_days_between ()

gint
g_date_days_between (const GDate *date1,
                     const GDate *date2);

Computes the number of days between two dates. If date2 is prior to date1 , the returned value is negative. Both dates must be valid.

Parameters

date1

the first date

 

date2

the second date

 

Returns

the number of days between date1 and date2


g_date_compare ()

gint
g_date_compare (const GDate *lhs,
                const GDate *rhs);

qsort()-style comparison function for dates. Both dates must be valid.

Parameters

lhs

first date to compare

 

rhs

second date to compare

 

Returns

0 for equal, less than zero if lhs is less than rhs , greater than zero if lhs is greater than rhs


g_date_clamp ()

void
g_date_clamp (GDate *date,
              const GDate *min_date,
              const GDate *max_date);

If date is prior to min_date , sets date equal to min_date . If date falls after max_date , sets date equal to max_date . Otherwise, date is unchanged. Either of min_date and max_date may be NULL. All non-NULL dates must be valid.

Parameters

date

a GDate to clamp

 

min_date

minimum accepted value for date

 

max_date

maximum accepted value for date

 

g_date_order ()

void
g_date_order (GDate *date1,
              GDate *date2);

Checks if date1 is less than or equal to date2 , and swap the values if this is not the case.

Parameters

date1

the first date

 

date2

the second date

 

g_date_get_day ()

GDateDay
g_date_get_day (const GDate *date);

Returns the day of the month. The date must be valid.

Parameters

date

a GDate to extract the day of the month from

 

Returns

day of the month


g_date_get_month ()

GDateMonth
g_date_get_month (const GDate *date);

Returns the month of the year. The date must be valid.

Parameters

date

a GDate to get the month from

 

Returns

month of the year as a GDateMonth


g_date_get_year ()

GDateYear
g_date_get_year (const GDate *date);

Returns the year of a GDate. The date must be valid.

Parameters

date

a GDate

 

Returns

year in which the date falls


g_date_get_julian ()

guint32
g_date_get_julian (const GDate *date);

Returns the Julian day or "serial number" of the GDate. The Julian day is simply the number of days since January 1, Year 1; i.e., January 1, Year 1 is Julian day 1; January 2, Year 1 is Julian day 2, etc. The date must be valid.

Parameters

date

a GDate to extract the Julian day from

 

Returns

Julian day


g_date_get_weekday ()

GDateWeekday
g_date_get_weekday (const GDate *date);

Returns the day of the week for a GDate. The date must be valid.

Parameters

date

a GDate

 

Returns

day of the week as a GDateWeekday.


g_date_get_day_of_year ()

guint
g_date_get_day_of_year (const GDate *date);

Returns the day of the year, where Jan 1 is the first day of the year. The date must be valid.

Parameters

date

a GDate to extract day of year from

 

Returns

day of the year


g_date_get_days_in_month ()

guint8
g_date_get_days_in_month (GDateMonth month,
                          GDateYear year);

Returns the number of days in a month, taking leap years into account.

Parameters

month

month

 

year

year

 

Returns

number of days in month during the year


g_date_is_first_of_month ()

gboolean
g_date_is_first_of_month (const GDate *date);

Returns TRUE if the date is on the first of a month. The date must be valid.

Parameters

date

a GDate to check

 

Returns

TRUE if the date is the first of the month


g_date_is_last_of_month ()

gboolean
g_date_is_last_of_month (const GDate *date);

Returns TRUE if the date is the last day of the month. The date must be valid.

Parameters

date

a GDate to check

 

Returns

TRUE if the date is the last day of the month


g_date_is_leap_year ()

gboolean
g_date_is_leap_year (GDateYear year);

Returns TRUE if the year is a leap year.

For the purposes of this function, leap year is every year divisible by 4 unless that year is divisible by 100. If it is divisible by 100 it would be a leap year only if that year is also divisible by 400.

Parameters

year

year to check

 

Returns

TRUE if the year is a leap year


g_date_get_monday_week_of_year ()

guint
g_date_get_monday_week_of_year (const GDate *date);

Returns the week of the year, where weeks are understood to start on Monday. If the date is before the first Monday of the year, return 0. The date must be valid.

Parameters

date

a GDate

 

Returns

week of the year


g_date_get_monday_weeks_in_year ()

guint8
g_date_get_monday_weeks_in_year (GDateYear year);

Returns the number of weeks in the year, where weeks are taken to start on Monday. Will be 52 or 53. The date must be valid. (Years always have 52 7-day periods, plus 1 or 2 extra days depending on whether it's a leap year. This function is basically telling you how many Mondays are in the year, i.e. there are 53 Mondays if one of the extra days happens to be a Monday.)

Parameters

year

a year

 

Returns

number of Mondays in the year


g_date_get_sunday_week_of_year ()

guint
g_date_get_sunday_week_of_year (const GDate *date);

Returns the week of the year during which this date falls, if weeks are understood to begin on Sunday. The date must be valid. Can return 0 if the day is before the first Sunday of the year.

Parameters

date

a GDate

 

Returns

week number


g_date_get_sunday_weeks_in_year ()

guint8
g_date_get_sunday_weeks_in_year (GDateYear year);

Returns the number of weeks in the year, where weeks are taken to start on Sunday. Will be 52 or 53. The date must be valid. (Years always have 52 7-day periods, plus 1 or 2 extra days depending on whether it's a leap year. This function is basically telling you how many Sundays are in the year, i.e. there are 53 Sundays if one of the extra days happens to be a Sunday.)

Parameters

year

year to count weeks in

 

Returns

the number of weeks in year


g_date_get_iso8601_week_of_year ()

guint
g_date_get_iso8601_week_of_year (const GDate *date);

Returns the week of the year, where weeks are interpreted according to ISO 8601.

Parameters

date

a valid GDate

 

Returns

ISO 8601 week number of the year.

Since: 2.6


g_date_strftime ()

gsize
g_date_strftime (gchar *s,
                 gsize slen,
                 const gchar *format,
                 const GDate *date);

Generates a printed representation of the date, in a locale-specific way. Works just like the platform's C library strftime() function, but only accepts date-related formats; time-related formats give undefined results. Date must be valid. Unlike strftime() (which uses the locale encoding), works on a UTF-8 format string and stores a UTF-8 result.

This function does not provide any conversion specifiers in addition to those implemented by the platform's C library. For example, don't expect that using g_date_strftime() would make the %F provided by the C99 strftime() work on Windows where the C library only complies to C89.

Parameters

s

destination buffer

 

slen

buffer size

 

format

format string

 

date

valid GDate

 

Returns

number of characters written to the buffer, or 0 the buffer was too small


g_date_to_struct_tm ()

void
g_date_to_struct_tm (const GDate *date,
                     struct tm *tm);

Fills in the date-related bits of a struct tm using the date value. Initializes the non-date parts with something sane but meaningless.

Parameters

date

a GDate to set the struct tm from

 

tm

struct tm to fill.

[not nullable]

g_date_valid ()

gboolean
g_date_valid (const GDate *date);

Returns TRUE if the GDate represents an existing day. The date must not contain garbage; it should have been initialized with g_date_clear() if it wasn't allocated by one of the g_date_new() variants.

Parameters

date

a GDate to check

 

Returns

Whether the date is valid


g_date_valid_day ()

gboolean
g_date_valid_day (GDateDay day);

Returns TRUE if the day of the month is valid (a day is valid if it's between 1 and 31 inclusive).

Parameters

day

day to check

 

Returns

TRUE if the day is valid


g_date_valid_month ()

gboolean
g_date_valid_month (GDateMonth month);

Returns TRUE if the month value is valid. The 12 GDateMonth enumeration values are the only valid months.

Parameters

month

month

 

Returns

TRUE if the month is valid


g_date_valid_year ()

gboolean
g_date_valid_year (GDateYear year);

Returns TRUE if the year is valid. Any year greater than 0 is valid, though there is a 16-bit limit to what GDate will understand.

Parameters

year

year

 

Returns

TRUE if the year is valid


g_date_valid_dmy ()

gboolean
g_date_valid_dmy (GDateDay day,
                  GDateMonth month,
                  GDateYear year);

Returns TRUE if the day-month-year triplet forms a valid, existing day in the range of days GDate understands (Year 1 or later, no more than a few thousand years in the future).

Parameters

day

day

 

month

month

 

year

year

 

Returns

TRUE if the date is a valid one


g_date_valid_julian ()

gboolean
g_date_valid_julian (guint32 julian_date);

Returns TRUE if the Julian day is valid. Anything greater than zero is basically a valid Julian, though there is a 32-bit limit.

Parameters

julian_date

Julian day to check

 

Returns

TRUE if the Julian day is valid


g_date_valid_weekday ()

gboolean
g_date_valid_weekday (GDateWeekday weekday);

Returns TRUE if the weekday is valid. The seven GDateWeekday enumeration values are the only valid weekdays.

Parameters

weekday

weekday

 

Returns

TRUE if the weekday is valid

Types and Values

G_USEC_PER_SEC

#define G_USEC_PER_SEC 1000000

Number of microseconds in one second (1 million). This macro is provided for code readability.


struct GTimeVal

struct GTimeVal {
  glong tv_sec;
  glong tv_usec;
};

Represents a precise time, with seconds and microseconds. Similar to the struct timeval returned by the gettimeofday() UNIX system call.

GLib is attempting to unify around the use of 64bit integers to represent microsecond-precision time. As such, this type will be removed from a future version of GLib.

Members

glong tv_sec;

seconds

 

glong tv_usec;

microseconds

 

struct GDate

struct GDate {
  guint julian_days : 32; /* julian days representation - we use a
                           *  bitfield hoping that 64 bit platforms
                           *  will pack this whole struct in one big
                           *  int
                           */

  guint julian : 1;    /* julian is valid */
  guint dmy    : 1;    /* dmy is valid */

  /* DMY representation */
  guint day    : 6;
  guint month  : 4;
  guint year   : 16;
};

Represents a day between January 1, Year 1 and a few thousand years in the future. None of its members should be accessed directly.

If the GDate is obtained from g_date_new(), it will be safe to mutate but invalid and thus not safe for calendrical computations.

If it's declared on the stack, it will contain garbage so must be initialized with g_date_clear(). g_date_clear() makes the date invalid but sane. An invalid date doesn't represent a day, it's "empty." A date becomes valid after you set it to a Julian day or you set a day, month, and year.

Members

guint julian_days : 32;

the Julian representation of the date

 

guint julian : 1;

this bit is set if julian_days is valid

 

guint dmy : 1;

this is set if day , month and year are valid

 

guint day : 6;

the day of the day-month-year representation of the date, as a number between 1 and 31

 

guint month : 4;

the day of the day-month-year representation of the date, as a number between 1 and 12

 

guint year : 16;

the day of the day-month-year representation of the date

 

GTime

typedef gint32  GTime;

Simply a replacement for time_t. It has been deprecated since it is not equivalent to time_t on 64-bit platforms with a 64-bit time_t. Unrelated to GTimer.

Note that GTime is defined to always be a 32-bit integer, unlike time_t which may be 64-bit on some systems. Therefore, GTime will overflow in the year 2038, and you cannot use the address of a GTime variable as argument to the UNIX time() function.

Instead, do the following:

1
2
3
4
5
time_t ttime;
GTime gtime;

time (&ttime);
gtime = (GTime)ttime;


enum GDateDMY

This enumeration isn't used in the API, but may be useful if you need to mark a number as a day, month, or year.

Members

G_DATE_DAY

a day

 

G_DATE_MONTH

a month

 

G_DATE_YEAR

a year

 

GDateDay

typedef guint8  GDateDay;   /* day of the month */

Integer representing a day of the month; between 1 and 31. G_DATE_BAD_DAY represents an invalid day of the month.


enum GDateMonth

Enumeration representing a month; values are G_DATE_JANUARY, G_DATE_FEBRUARY, etc. G_DATE_BAD_MONTH is the invalid value.

Members

G_DATE_BAD_MONTH

invalid value

 

G_DATE_JANUARY

January

 

G_DATE_FEBRUARY

February

 

G_DATE_MARCH

March

 

G_DATE_APRIL

April

 

G_DATE_MAY

May

 

G_DATE_JUNE

June

 

G_DATE_JULY

July

 

G_DATE_AUGUST

August

 

G_DATE_SEPTEMBER

September

 

G_DATE_OCTOBER

October

 

G_DATE_NOVEMBER

November

 

G_DATE_DECEMBER

December

 

GDateYear

typedef guint16 GDateYear;

Integer representing a year; G_DATE_BAD_YEAR is the invalid value. The year must be 1 or higher; negative (BC) years are not allowed. The year is represented with four digits.


enum GDateWeekday

Enumeration representing a day of the week; G_DATE_MONDAY, G_DATE_TUESDAY, etc. G_DATE_BAD_WEEKDAY is an invalid weekday.

Members

G_DATE_BAD_WEEKDAY

invalid value

 

G_DATE_MONDAY

Monday

 

G_DATE_TUESDAY

Tuesday

 

G_DATE_WEDNESDAY

Wednesday

 

G_DATE_THURSDAY

Thursday

 

G_DATE_FRIDAY

Friday

 

G_DATE_SATURDAY

Saturday

 

G_DATE_SUNDAY

Sunday

 

G_DATE_BAD_DAY

#define G_DATE_BAD_DAY    0U

Represents an invalid GDateDay.


G_DATE_BAD_JULIAN

#define G_DATE_BAD_JULIAN 0U

Represents an invalid Julian day number.


G_DATE_BAD_YEAR

#define G_DATE_BAD_YEAR   0U

Represents an invalid year.

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