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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | VERSIONS | STANDARDS | HISTORY | NOTES | SEE ALSO | COLOPHON |
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tm(3type) tm(3type)
tm - broken-down time
Standard C library (libc)
#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)):
tm_gmtoff, tm_zone:
Since glibc 2.20:
_DEFAULT_SOURCE
glibc 2.20 and earlier:
_BSD_SOURCE
Describes time, broken down into distinct components.
tm_isdst 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.
tm_gmtoff is the difference, in seconds, of the timezone
represented by this broken-down time and UTC (this is the
additive inverse of timezone(3)).
tm_zone is the equivalent of tzname(3) for the timezone
represented by this broken-down time.
In C90, tm_sec 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), as a variable, is an XSI extension: some systems
provide the V7-compatible timezone(3) function. The tm_gmtoff
field provides an alternative (with the opposite sign) for those
systems.
tm_zone points to static storage and may be overridden on
subsequent calls to localtime(3) and similar functions (however,
this never happens under glibc).
C23, POSIX.1-2024.
C89, POSIX.1-1988.
tm_gmtoff and tm_zone originate from 4.3BSD-Tahoe (where tm_zone
is a char *), and were first standardized in POSIX.1-2024.
tm_sec can represent a leap second with the value 60.
ctime(3), strftime(3), strptime(3), time(7)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.9.1.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2024-06-26. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.9.1 2024-06-12 tm(3type)
Pages that refer to this page: ctime(3), strptime(3), tzset(3), time(7)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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