ctime(3C)ctime(3C)NAMEctime(), ctime_r(), asctime(), asctime_r(), daylight(), difftime(),
gmtime(), gmtime_r(), localtime(), localtime_r(), mktime(), timezone(),
tzname(), tzset() - convert date and time to string
SYNOPSISDESCRIPTION
Convert the broken-down time contained in the structure pointed to by
timeptr and return a pointer to a 26-character string
in the form:
All the fields have constant width.
returns NULL and sets errno to if tm_year in is less
than 0 or is greater than 8099. In both 32-bit and
64-bit HP-UX, the minimum date supported by is Janu‐
ary 1 00:00:00 1900 and the maximum date supported by
is December 31 23:59:59 9999.
is identical to except that it places the result in the user supplied
and returns a pointer to upon success. A buffer
length of at least 26 is required.
Convert the calendar time pointed to by
timer, representing the time in seconds since the
Epoch, and return a pointer to the local time in the
form of a string. Equivalent to:
The minimum date supported by in both 32-bit and
64-bit HP-UX is Friday December 13 20:45:52 UTC 1901.
The maximum dates supported by are Tuesday January 19
03:14:07 UTC 2038 and Friday December 31 23:59:59 UTC
9999 in 32-bit HP-UX and 64-bit HP-UX, respectively.
In 64-bit HP-UX, returns NULL and sets errno to if
timer is less than the number of seconds that corre‐
sponds to the minimum date supported (i.e., as
defined in or exceeds the number of seconds that cor‐
responds to the maximum date supported.
is identical to except that it places the result in the user supplied
and returns a pointer to upon success. A buffer
length of at least 26 is required.
Return the difference in seconds between two calendar times:
time1 - time0.
Convert directly to Coordinated Universal Time (UTC),
the time standard used by the HP-UX operating system.
returns a pointer to the structure described below.
The minimum date supported by in both 32-bit and
64-bit HP-UX is Friday December 13 20:45:52 UTC 1901.
The maximum dates supported by are Tuesday January 19
03:14:07 UTC 2038 and Friday December 31 23:59:59 UTC
9999 in 32-bit HP-UX and 64-bit HP-UX, respectively.
In 64-bit HP-UX, returns NULL and sets errno to if
timer is less than the number of seconds that corre‐
sponds to the minimum date supported (i.e., as
defined in or exceeds the number of seconds that cor‐
responds to the maximum date supported.
is identical to except that stores the result in the pointed to by
and returns upon success.
Correct for the time zone and any summer time zone adjustments
(such as Daylight Savings Time in the USA), according
to the contents of the environment variable (see
below). returns a pointer to the structure described
below.
The minimum date supported by in both 32-bit and
64-bit HP-UX is Friday December 13 20:45:52 UTC 1901.
The maximum dates supported by are Tuesday January 19
03:14:07 UTC 2038 and Friday December 31 23:59:59 UTC
9999 in 32-bit HP-UX and 64-bit HP-UX, respectively.
In 64-bit HP-UX, returns NULL and sets errno to if
timer is less than the number of seconds that corre‐
sponds to the minimum date supported (i.e., as
defined in or exceeds the number of seconds that cor‐
responds to the maximum date supported.
is identical to except that stores the result in the pointed to by
and returns upon success.
Convert the broken-down time (expressed as local time)
in the structure pointed to by timeptr into a calen‐
dar time value with the same encoding as that of the
values returned by The original values of the and
components of the structure are ignored, and the
original values of the other components are not
restricted to the ranges indicated below.
A positive or zero value for causes to initially pre‐
sume that Daylight Saving Time respectively is or is
not in effect for the specified time. A negative
value for causes to attempt to determine whether Day‐
light Saving Time is in effect for the specified
time.
Upon successful completion, all the components are
set to represent the specified calendar time, but
with their values forced to the ranges indicated
below. The final value of is not set until and are
determined. returns the specified calendar time
encoded as a value of type
The minimum date supported by in both 32-bit and
64-bit HP-UX is Friday December 13 20:45:52 UTC 1901.
The maximum dates supported by are Tuesday January 19
03:14:07 UTC 2038 and Friday December 31 23:59:59 UTC
9999 in 32-bit HP-UX and 64-bit HP-UX, respectively.
For 32-bit if the calendar time cannot be repre‐
sented, the function returns the value and sets to
Note the value also corresponds to the time 23:59:59
on Dec 31, 1969 (plus or minus time zone and Daylight
Saving Time adjustments). Thus it is necessary to
check both the return value and to reliably detect an
error condition.
The behavior of 64-bit beyond the supported ranges is
undefined.
Sets the values of the external variables
timezone, daylight, and tzname according to the con‐
tents of the environment variable (independent of any
time value). The functions and (see strftime(3C))
call and use the values returned in the external
variables described below for their operations. can
also be called directly by the user.
When the environment variable is not set, checks the
default file for the timezone value and sets timezone
values based on that. The file contains the timezone
value used by when the environment variable is not
set. The format for the file is same as format with‐
out the prefix Please check environ(5) for format.
If the value of the timezone cannot be determined
using the environment variable or the file it is set
to the default value of EST5EDT. If the timezone is
set to the default value of EST5EDT and the timezone
adjustment file is not available, the timezone is set
to a default value of UTC (Coordinated Universal
Time).
can be modified for an appropriate default value for
timezone.
The header file contains declarations of all relevant functions and
externals. It also contains the structure, which includes the follow‐
ing members:
int tm_sec; /* seconds after the minute - [0,61] */
int tm_min; /* minutes after the hour - [0,59] */
int tm_hour; /* hours - [0,23] */
int tm_mday; /* day of month - [1,31] */
int tm_mon; /* month of year - [0,11] */
int tm_year; /* years since 1900 */
int tm_wday; /* days since Sunday - [0,6] */
int tm_yday; /* days since January 1 - [0,365] */
int tm_isdst; /* daylight savings time flag */
The value of is positive if a summer time zone adjustment such as Day‐
light Savings Time is in effect, zero if not in effect, and negative if
the information is not available.
The external variable contains the difference, in seconds, between UTC
and local standard time (for example, in the U.S. Eastern time zone
(EST), is 5*60*60). The external variable is non-zero only if a summer
time zone adjustment is specified in the environment variable. The
external variable contains the local standard and local summer time
zone abbreviations as specified by the environment variable.
EXTERNAL INFLUENCES
Locale
The category determines the interpretation of the bytes within format
as single and/or multi-byte characters.
Environment Variables
The function uses the contents of to set the values of the external
variables and also determines the time zone name substituted for the
and directives and the time zone adjustments performed by and Two meth‐
ods for specifying a time zone within are described in environ(5).
International Code Set Support
Single and multibyte character code sets are supported.
RETURN VALUE
For and if the buffer is of insufficient length, a NULL is returned and
errno set to
and return a NULL and set errno to if NULL pointers are passed in as
arguments.
A NULL is returned and errno is set to if the input to the following
routines is not within the supported range:
APPLICATION USAGE
The return values for and point to static data whose contents is over‐
written by each call.
WARNINGS
Users of and should also note that these functions now conform to
POSIX.1c. The old prototypes of these functions are supported for com‐
patibility with existing DCE applications only.
The range of extends to 61 to allow for the occasional one or two leap
seconds. However, the "seconds since the Epoch" value returned by (see
time(2)) and passed as the timer argument does not include accumulated
leap seconds. The structure generated by and will never reflect any
leap seconds. Upon successful completion, forces the value of the com‐
ponent to the range [0,59].
AUTHOR
was developed by AT&T and HP.
SEE ALSOtime(2), getdate(3C), setlocale(3C), strftime(3C), tztab(4), envi‐
ron(5), lang(5), langinfo(5), thread_safety(5).
STANDARDS CONFORMANCEctime(3C)
