dysize(3) — Linux manual page

dysize(3)                Library Functions Manual               dysize(3)

NAME         top

       dysize - get number of days for a given year

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #include <time.h>

       int dysize(int year);

   Feature Test Macro Requirements for glibc (see
   feature_test_macros(7)):

       dysize():
           Since glibc 2.19:
               _DEFAULT_SOURCE
           glibc 2.19 and earlier:
               _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION         top

       The function returns 365 for a normal year and 366 for a leap
       year.  The calculation for leap year is based on:

           (year) %4 == 0 && ((year) %100 != 0 || (year) %400 == 0)

       The formula is defined in the macro __isleap(year) also found in
       <time.h>.

ATTRIBUTES         top

       For an explanation of the terms used in this section, see
       attributes(7).
       ┌──────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                            │ Attribute     │ Value   │
       ├──────────────────────────────────────┼───────────────┼─────────┤
       │ dysize()                             │ Thread safety │ MT-Safe │
       └──────────────────────────────────────┴───────────────┴─────────┘

STANDARDS         top

       None.

HISTORY         top

       SunOS 4.x.

       This is a compatibility function only.  Don't use it in new
       programs.

SEE ALSO         top

       strftime(3)

COLOPHON         top

       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-6.15.tar.gz
       fetched from
       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
       2025-08-11.  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 6.15            2025-05-17                      dysize(3)

HTML rendering created 2025-09-06 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.