reference/datetime/functions/strtotime.xml
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5c951013ca04161992efed8b86fb40f55669958e
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and will try to parse that format into a Unix timestamp (the number of
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seconds since January 1 1970 00:00:00 UTC), relative to the timestamp given
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in <parameter>baseTimestamp</parameter>, or the current time if
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<parameter>baseTimestamp</parameter> is not supplied.
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<parameter>baseTimestamp</parameter> is not supplied. The date string parsing
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is defined in <link linkend="datetime.formats">Date and Time Formats</link>, and
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has several subtle considerations. Reviewing the full details there is strongly
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recommended.
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</simpara>
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<warning>
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<para>
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&reftitle.notes;
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<note>
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<para>
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"Relative" date in this case also means that if a particular component
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of the date/time stamp is not provided, it will be taken verbatim from
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the <parameter>baseTimestamp</parameter>. That is, <code>strtotime('February')</code>,
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if run on the 31st of May 2022, will be interpreted as <literal>31 February 2022</literal>,
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which will overflow into a timestamp on <literal>3 March</literal>.
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(In a leap year, it would be <literal>2 March</literal>.) Using
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<code>strtotime('1 February')</code> or <code>strtotime('first day of February')</code>
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would avoid that problem.
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</para>
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</note>
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<note>
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<para>
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If the number of the year is specified in a two digit format, the values
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between 00-69 are mapped to 2000-2069 and 70-99 to 1970-1999. See the notes
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below for possible differences on 32bit systems (possible dates might end on
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</note>
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<note>
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<para>
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Dates in the <literal>m/d/y</literal> or <literal>d-m-y</literal> formats
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are disambiguated by looking at the separator between the various
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components: if the separator is a slash (<literal>/</literal>), then the
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American <literal>m/d/y</literal> is assumed; whereas if the separator is a
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dash (<literal>-</literal>) or a dot (<literal>.</literal>), then the
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European <literal>d-m-y</literal> format is assumed.
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If, however, the year is given in a two digit format and the separator is a
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dash (<literal>-</literal>), the date string is parsed as
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<literal>y-m-d</literal>.
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</para>
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<para>
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To avoid potential ambiguity, it's best to use ISO 8601
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(<literal>YYYY-MM-DD</literal>) dates or
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<methodname>DateTime::createFromFormat</methodname> when possible.
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</para>
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</note>
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<note>
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<para>
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Using this function for mathematical operations is not advisable.
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It is better to use <methodname>DateTime::add</methodname> and
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<methodname>DateTime::sub</methodname>.
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&reftitle.seealso;
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<para>
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<simplelist>
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<member><classname>DateTimeImmutable</classname></member>
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<member><methodname>DateTimeImmutable::createFromFormat</methodname></member>
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<member><link linkend="datetime.formats">Date and Time Formats</link></member>
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<member><methodname>DateTime::createFromFormat</methodname></member>
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<member><function>checkdate</function></member>
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<member><function>strptime</function></member>
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</simplelist>
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