Functions
g_get_current_time ()
void
g_get_current_time (GTimeVal *result);
g_get_current_time has been deprecated since version 2.62 and should not be used in newly-written code.
GTimeVal is not year-2038-safe. Use g_get_real_time()
instead.
Equivalent to the UNIX gettimeofday() function, but portable.
You may find g_get_real_time() to be more convenient.
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.
g_time_val_add ()
void
g_time_val_add (GTimeVal *time_,
glong microseconds);
g_time_val_add has been deprecated since version 2.62 and should not be used in newly-written code.
GTimeVal is not year-2038-safe. Use guint64 for
representing microseconds since the epoch, or use GDateTime.
Adds the given number of microseconds to time_
. microseconds
can
also be negative to decrease the value of 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.)
Any leading or trailing space in iso_date
is ignored.
This function was deprecated, along with GTimeVal itself, in GLib 2.62.
Equivalent functionality is available using code like:
Returns
TRUE if the conversion was successful.
Since: 2.12
g_time_val_to_iso8601 ()
gchar *
g_time_val_to_iso8601 (GTimeVal *time_);
g_time_val_to_iso8601 has been deprecated since version 2.62 and should not be used in newly-written code.
GTimeVal is not year-2038-safe. Use
g_date_time_format_iso8601(dt) instead.
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. Note also that since
GTimeVal stores the number of seconds as a glong, on 32-bit systems it
is subject to the year 2038 problem. Accordingly, since GLib 2.62, this
function has been deprecated. Equivalent functionality is available using:
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.
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 safe 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.
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.
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 safe 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().
g_date_copy ()
GDate *
g_date_copy (const GDate *date);
Copies a GDate to a newly-allocated GDate. If the input was invalid
(as determined by g_date_valid()), the invalid state will be copied
as is into the new object.
Returns
a newly-allocated GDate initialized from date
.
[transfer full]
Since: 2.56
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.
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.
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.
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.
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.
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:
Since: 2.10
g_date_set_time_val ()
void
g_date_set_time_val (GDate *date,
GTimeVal *timeval);
g_date_set_time_val has been deprecated since version 2.62 and should not be used in newly-written code.
GTimeVal is not year-2038-safe. Use g_date_set_time_t()
instead.
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.
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).
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
g_date_get_day ()
GDateDay
g_date_get_day (const GDate *date);
Returns the day of the month. The date must be valid.
g_date_get_month ()
GDateMonth
g_date_get_month (const GDate *date);
Returns the month of the year. The date must be valid.
g_date_get_year ()
GDateYear
g_date_get_year (const GDate *date);
Returns the year of a GDate. The date must be valid.
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.
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.
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.
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.
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.
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.
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.
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.
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.)
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.
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.)
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.
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.
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 safe but meaningless.
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.
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).
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.
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.
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).
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.
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.
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;
};
GTimeVal has been deprecated since version 2.62 and should not be used in newly-written code.
Use GDateTime or guint64 instead.
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 64-bit integers to
represent microsecond-precision time. As such, this type will be
removed from a future version of GLib. A consequence of using glong for
tv_sec is that on 32-bit systems GTimeVal is subject to the year 2038
problem.
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 safe. 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.
GTime
typedef gint32 GTime GLIB_DEPRECATED_TYPE_IN_2_62_FOR(GDateTime);
GTime has been deprecated since version 2.62 and should not be used in newly-written code.
This is not Y2038-safe.
Use GDateTime or time_t instead.
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:
enum GDateDMY
GDateDMY is deprecated and should not be used in newly-written code.
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.
GDateDay
typedef guint8 GDateDay; /* day of the month */
GDateDay is deprecated and should not be used in newly-written code.
Integer representing a day of the month; between 1 and 31.
G_DATE_BAD_DAY represents an invalid day of the month.
GDateYear
typedef guint16 GDateYear;
GDateYear is deprecated and should not be used in newly-written code.
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.
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.