TZ::Rule Struct Reference

Describe rules for when daylight/summer time begins, and when standard time begins. More...

#include <Timezone.h>

Collaboration diagram for TZ::Rule:

Classes
struct	Time

Public Types
using	Tag = DateTime::ZoneInfo::Tag

Public Member Functions
int	offsetSecs () const
time_t	operator() (unsigned year) const
	Convert the given time change rule to a time_t value for the given year. More...
	operator int () const
	Obtain a numeric value for comparison purposes. More...
bool	operator== (const Rule &other) const
bool	operator!= (const Rule &other) const

Public Attributes
Tag	tag
	e.g. DST, UTC, etc. More...
week_t	week: 4
dow_t	dow: 4
month_t	month: 8
Time	time
int16_t	offsetMins
	Offset from UTC. More...

Static Public Attributes
static const Rule	UTC

Detailed Description

Describe rules for when daylight/summer time begins, and when standard time begins.

This rule structure is an exact analogue of the POSIX 'M'-style rules, which are the only ones in general use. The GLIBC manual page provides a good overview of these rules:

    https://sourceware.org/glibc/manual/2.39/html_node/TZ-Variable.html

Original versions of this library only allowed a single value for hours, for example:

    {"BST", Last, Sun, Mar, 1, 60}

However, some zones also require a minute value, such as Pacific/Chatham which changes at 03:45. We can use a fractional value (3.75) for this:

    {"+1245", First, Sun, Apr, 3.75, 765}

Western greenland has a negative hours value, America/Godthab:

{"-01", Last, Sun, Mar, -1, -60}

Note that at time of writing newlib (the embedded C library) does not support negative time values (via tzset) and produces incorrect results.

Member Typedef Documentation

Tag

using TZ::Rule::Tag = DateTime::ZoneInfo::Tag

Member Function Documentation

offsetSecs()

int TZ::Rule::offsetSecs ( ) const

inline

operator int()

TZ::Rule::operator int ( ) const

inlineexplicit

Obtain a numeric value for comparison purposes.

operator!=()

bool TZ::Rule::operator!= ( const Rule &  other ) const

inline

operator()()

time_t TZ::Rule::operator()

(

unsigned

year

)

const

Convert the given time change rule to a time_t value for the given year.

Parameters

year	Which year to work with

Return values

time_t

Timestamp for the given time change

operator==()

bool TZ::Rule::operator== ( const Rule &  other ) const

inline

Member Data Documentation

dow

dow_t TZ::Rule::dow

month

month_t TZ::Rule::month

offsetMins

int16_t TZ::Rule::offsetMins

Offset from UTC.

tag

Tag TZ::Rule::tag

e.g. DST, UTC, etc.

time

Time TZ::Rule::time

UTC

const Rule TZ::Rule::UTC

static

week

week_t TZ::Rule::week

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The documentation for this struct was generated from the following file:

• Timezone.h