man3/dysize.3

.\"  Copyright 2001 Walter Harms (walter.harms@informatik.uni-oldenburg.de)
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.\" aeb: some corrections
.TH DYSIZE 3 2016-03-15 "GNU" "Linux Programmer's Manual"
.SH NAME
dysize \- get number of days for a given year
.SH SYNOPSIS
.B "#include <time.h>"
.PP
.BI "int dysize(int " year );
.PP
.in -4n
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
.PP
.BR dysize ():
    Since glibc 2.19:
        _DEFAULT_SOURCE
    Glibc 2.19 and earlier:
        _BSD_SOURCE || _SVID_SOURCE
.SH DESCRIPTION
The function returns 365 for a normal year and 366 for a leap year.
The calculation for leap year is based on:
.PP
.in +4n
.EX
(year) %4 == 0 && ((year) %100 != 0 || (year) %400 == 0)
.EE
.in
.PP
The formula is defined in the macro
.I __isleap(year)
also found in
.IR <time.h> .
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lb lb lb
l l l.
Interface	Attribute	Value
T{
.BR dysize ()
T}	Thread safety	MT-Safe
.TE
.SH CONFORMING TO
This function occurs in SunOS 4.x.
.SH NOTES
This is a compatibility function only.
Don't use it in new programs.
.\" The SCO version of this function had a year-2000 problem.
.SH SEE ALSO
.BR strftime (3)