dysize(3) Library Functions Manual dysize(3)

dysize - get number of days for a given year

Standard C library (libc, -lc)

#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

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>.

For an explanation of the terms used in this section, see attributes(7).

Interface Attribute Value
dysize () Thread safety MT-Safe

None.

SunOS 4.x.

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

strftime(3)

2023-10-31 Linux man-pages 6.7