dysize man page
dysize — get number of days for a given year
int dysize(int year);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
Since glibc 2.19:
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).
This function occurs in SunOS 4.x.
This is a compatibility function only. Don't use it in new programs.
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