tm(3type) - Linux manual page (original) (raw)
tm(3type) tm(3type)
NAME top
tm - broken-down timeLIBRARY top
Standard C library (_libc_)SYNOPSIS top
**#include <time.h>**
**struct tm {**
**int tm_sec;** /* Seconds [**0**, **60**] */
**int tm_min;** /* Minutes [**0**, **59**] */
**int tm_hour;** /* Hour [**0**, **23**] */
**int tm_mday;** /* Day of the month [**1**, **31**] */
**int tm_mon;** /* Month [**0**, **11**] (January = **0**) */
**int tm_year;** /* Year minus **1900** */
**int tm_wday;** /* Day of the week [**0**, **6**] (Sunday = **0**) */
**int tm_yday;** /* Day of the year [**0**, **365**] (Jan/01 = **0**) */
**int tm_isdst;** /* Daylight savings flag */
**long tm_gmtoff;** /* Seconds East of UTC */
**const char *tm_zone;** /* Timezone abbreviation */
**};**Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
_tmgmtoff_, _tmzone_:
Since glibc 2.20:
_DEFAULT_SOURCE
glibc 2.20 and earlier:
_BSD_SOURCEDESCRIPTION top
Describes time, broken down into distinct components.
_tmisdst_ describes whether daylight saving time is in effect at
the time described. The value is positive if daylight saving time
is in effect, zero if it is not, and negative if the information
is not available.
_tmgmtoff_ is the difference, in seconds, of the timezone
represented by this broken-down time and UTC (this is the additive
inverse of [timezone(3)](../man3/timezone.3.html)).
_tmzone_ is the equivalent of [tzname(3)](../man3/tzname.3.html) for the timezone
represented by this broken-down time.VERSIONS top
In C90, _tmsec_ could represent values in the range [**0**, **61**], which
could represent a double leap second. UTC doesn't permit double
leap seconds, so it was limited to **60** in C99.
[timezone(3)](../man3/timezone.3.html), as a variable, is an XSI extension: some systems
provide the V7-compatible [timezone(3)](../man3/timezone.3.html) function. The _tmgmtoff_
field provides an alternative (with the opposite sign) for those
systems.
_tmzone_ points to static storage and may be overridden on
subsequent calls to [localtime(3)](../man3/localtime.3.html) and similar functions (however,
this never happens under glibc).STANDARDS top
C23, POSIX.1-2024.HISTORY top
C89, POSIX.1-1988.
_tmgmtoff_ and _tmzone_ originate from 4.3BSD-Tahoe (where _tmzone_
is a _char *_), and were first standardized in POSIX.1-2024.NOTES top
_tmsec_ can represent a leap second with the value **60**.SEE ALSO top
[ctime(3)](../man3/ctime.3.html), [strftime(3)](../man3/strftime.3.html), [strptime(3)](../man3/strptime.3.html), [time(7)](../man7/time.7.html)COLOPHON top
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man-pages@man7.orgLinux man-pages 6.10 2024-06-12 tm(3type)
Pages that refer to this page:ctime(3), strptime(3), tzset(3), time(7)