php-doc-en/reference/datetime/functions/date-sunset.xml
Sergey Panteleev 8a2141dcc0
Deprecated functions and constants
Co-authored-by: Christoph M. Becker <cmbecker69@gmx.de>

Closes GH-981.
2021-10-04 16:53:40 +02:00

278 lines
8 KiB
XML

<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<refentry xml:id="function.date-sunset" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
<refnamediv>
<refname>date_sunset</refname>
<refpurpose>
Returns time of sunset for a given day and location
</refpurpose>
</refnamediv>
<refsynopsisdiv>
&warn.deprecated.function-8-1-0;
</refsynopsisdiv>
<refsect1 role="description">
&reftitle.description;
<methodsynopsis>
<type class="union"><type>string</type><type>int</type><type>float</type><type>false</type></type><methodname>date_sunset</methodname>
<methodparam><type>int</type><parameter>timestamp</parameter></methodparam>
<methodparam choice="opt"><type>int</type><parameter>returnFormat</parameter><initializer><constant>SUNFUNCS_RET_STRING</constant></initializer></methodparam>
<methodparam choice="opt"><type class="union"><type>float</type><type>null</type></type><parameter>latitude</parameter><initializer>&null;</initializer></methodparam>
<methodparam choice="opt"><type class="union"><type>float</type><type>null</type></type><parameter>longitude</parameter><initializer>&null;</initializer></methodparam>
<methodparam choice="opt"><type class="union"><type>float</type><type>null</type></type><parameter>zenith</parameter><initializer>&null;</initializer></methodparam>
<methodparam choice="opt"><type class="union"><type>float</type><type>null</type></type><parameter>utcOffset</parameter><initializer>&null;</initializer></methodparam>
</methodsynopsis>
<para>
<function>date_sunset</function> returns the sunset time for a given
day (specified as a <parameter>timestamp</parameter>) and location.
</para>
</refsect1>
<refsect1 role="parameters">
&reftitle.parameters;
<para>
<variablelist>
<varlistentry>
<term><parameter>timestamp</parameter></term>
<listitem>
<para>
The <parameter>timestamp</parameter> of the day from which the sunset
time is taken.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>returnFormat</parameter></term>
<listitem>
<para>
<table>
<title><parameter>returnFormat</parameter> constants</title>
<tgroup cols="2">
<thead>
<row>
<entry>constant</entry>
<entry>description</entry>
<entry>example</entry>
</row>
</thead>
<tbody>
<row>
<entry>SUNFUNCS_RET_STRING</entry>
<entry>returns the result as <type>string</type></entry>
<entry>16:46</entry>
</row>
<row>
<entry>SUNFUNCS_RET_DOUBLE</entry>
<entry>returns the result as <type>float</type></entry>
<entry>16.78243132</entry>
</row>
<row>
<entry>SUNFUNCS_RET_TIMESTAMP</entry>
<entry>returns the result as <type>int</type> (timestamp)</entry>
<entry>1095034606</entry>
</row>
</tbody>
</tgroup>
</table>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>latitude</parameter></term>
<listitem>
<para>
Defaults to North, pass in a negative value for South.
See also: <link linkend="ini.date.default-latitude">date.default_latitude</link>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>longitude</parameter></term>
<listitem>
<para>
Defaults to East, pass in a negative value for West.
See also: <link linkend="ini.date.default-longitude">date.default_longitude</link>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>zenith</parameter></term>
<listitem>
<para>
<parameter>zenith</parameter> is the angle between the center of the sun
and a line perpendicular to earth's surface. It defaults to
<link linkend="ini.date.sunset-zenith">date.sunset_zenith</link>
<table>
<title>Common <parameter>zenith</parameter> angles</title>
<tgroup cols="2">
<thead>
<row>
<entry>Angle</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry>90°50'</entry>
<entry>Sunset: the point where the sun becomes invisible.</entry>
</row>
<row>
<entry>96°</entry>
<entry>Civil twilight: conventionally used to signify the end of dusk.</entry>
</row>
<row>
<entry>102°</entry>
<entry>Nautical twilight: the point at which the horizon ends being visible at sea.</entry>
</row>
<row>
<entry>108°</entry>
<entry>Astronomical twilight: the point at which the sun ends being the source of any illumination.</entry>
</row>
</tbody>
</tgroup>
</table>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>utcOffset</parameter></term>
<listitem>
<para>
Specified in hours.
The <parameter>utcOffset</parameter> is ignored, if
<parameter>returnFormat</parameter> is
<constant>SUNFUNCS_RET_TIMESTAMP</constant>.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1 role="returnvalues">
&reftitle.returnvalues;
<para>
Returns the sunset time in a specified <parameter>returnFormat</parameter> on
success&return.falseforfailure;. One potential reason for failure is that the
sun does not set at all, which happens inside the polar circles for part of
the year.
</para>
</refsect1>
<refsect1 role="errors">
&reftitle.errors;
&date.timezone.errors.description;
</refsect1>
<refsect1 role="changelog">
&reftitle.changelog;
<para>
<informaltable>
<tgroup cols="2">
<thead>
<row>
<entry>&Version;</entry>
<entry>&Description;</entry>
</row>
</thead>
<tbody>
<row>
<entry>8.1.0</entry>
<entry>
This function has been deprecated in favor of <function>date_sun_info</function>.
</entry>
</row>
<row>
<entry>8.0.0</entry>
<entry>
<parameter>latitude</parameter>, <parameter>longitude</parameter>,
<parameter>zenith</parameter> and <parameter>utcOffset</parameter> are nullable now.
</entry>
</row>
</tbody>
</tgroup>
</informaltable>
</para>
</refsect1>
<refsect1 role="examples">
&reftitle.examples;
<para>
<example>
<title><function>date_sunset</function> example</title>
<programlisting role="php">
<![CDATA[
<?php
/* calculate the sunset time for Lisbon, Portugal
Latitude: 38.4 North
Longitude: 9 West
Zenith ~= 90
offset: +1 GMT
*/
echo date("D M d Y"). ', sunset time : ' .date_sunset(time(), SUNFUNCS_RET_STRING, 38.4, -9, 90, 1);
?>
]]>
</programlisting>
&example.outputs.similar;
<screen>
<![CDATA[
Mon Dec 20 2004, sunset time : 18:13
]]>
</screen>
</example>
<example>
<title>No sunset</title>
<programlisting role="php">
<![CDATA[
<?php
$solstice = strtotime('2017-12-21');
var_dump(date_sunset($solstice, SUNFUNCS_RET_STRING, 69.245833, -53.537222));
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
bool(false)
]]>
</screen>
</example>
</para>
</refsect1>
<refsect1 role="seealso">
&reftitle.seealso;
<para>
<simplelist>
<member><function>date_sunrise</function></member>
<member><function>date_sun_info</function></member>
</simplelist>
</para>
</refsect1>
</refentry>
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