appendices/migration74/new-features.xml
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<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<sect1 xml:id="migration74.new-features" xmlns:xlink="http://www.w3.org/1999/xlink">
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<title>New Features</title>
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<sect2 xml:id="migration74.new-features.core">
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<title>PHP Core</title>
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<sect3 xml:id="migration74.new-features.core.typed-properties">
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<title>Typed properties</title>
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<para>
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Class properties now support type declarations.
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<informalexample>
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<programlisting role="php">
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<![CDATA[
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<?php
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class User {
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public int $id;
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public string $name;
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}
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?>
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]]>
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</programlisting>
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</informalexample>
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The above example will enforce that <literal>$user->id</literal> can only be
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assigned <type>int</type> values and <literal>$user->name</literal> can
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only be assigned <type>string</type> values.
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</para>
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</sect3>
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<sect3 xml:id="migration74.new-features.core.arrow-functions">
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<title>Arrow functions</title>
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<para>
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<link linkend="functions.arrow">Arrow functions</link> provide a
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shorthand syntax for defining functions
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with implicit by-value scope binding.
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<informalexample>
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<programlisting role="php">
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<![CDATA[
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<?php
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$factor = 10;
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$nums = array_map(fn($n) => $n * $factor, [1, 2, 3, 4]);
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// $nums = array(10, 20, 30, 40);
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?>
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]]>
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</programlisting>
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</informalexample>
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</para>
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</sect3>
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<sect3 xml:id="migration74.new-features.core.type-variance">
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<title>Limited return type covariance and argument type contravariance</title>
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<para>
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The following code will now work:
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<informalexample>
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<programlisting role="php">
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<![CDATA[
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<?php
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class A {}
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class B extends A {}
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class Producer {
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public function method(): A {}
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}
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class ChildProducer extends Producer {
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public function method(): B {}
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}
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?>
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]]>
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</programlisting>
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</informalexample>
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Full variance support is only available if autoloading is used. Inside a
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single file only non-cyclic type references are possible, because all
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classes need to be available before they are referenced.
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</para>
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</sect3>
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<sect3 xml:id="migration74.new-features.core.null-coalescing-assignment-operator">
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<title>Null coalescing assignment operator</title>
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<para>
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<informalexample>
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<programlisting role="php">
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<![CDATA[
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<?php
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$array['key'] ??= computeDefault();
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// is roughly equivalent to
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if (!isset($array['key'])) {
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$array['key'] = computeDefault();
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}
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?>
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]]>
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</programlisting>
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</informalexample>
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</para>
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</sect3>
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<sect3 xml:id="migration74.new-features.core.unpack-inside-array">
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<title>Unpacking inside arrays</title>
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<para>
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<informalexample>
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<programlisting role="php">
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<![CDATA[
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<?php
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$parts = ['apple', 'pear'];
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$fruits = ['banana', 'orange', ...$parts, 'watermelon'];
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// ['banana', 'orange', 'apple', 'pear', 'watermelon'];
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?>
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]]>
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</programlisting>
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</informalexample>
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</para>
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</sect3>
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<sect3 xml:id="migration74.new-features.core.numeric-literal-separator">
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<title>Numeric literal separator</title>
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<para>
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Numeric literals can contain underscores between digits.
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<informalexample>
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<programlisting role="php">
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<![CDATA[
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<?php
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6.674_083e-11; // float
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299_792_458; // decimal
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0xCAFE_F00D; // hexadecimal
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0b0101_1111; // binary
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?>
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]]>
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</programlisting>
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</informalexample>
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</para>
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</sect3>
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<sect3 xml:id="migration74.new-features.core.weakreference">
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<title>Weak references</title>
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<para>
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<link linkend="class.weakreference">Weak references</link> allow the programmer to retain a reference to an object
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that does not prevent the object from being destroyed.
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</para>
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</sect3>
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<sect3 xml:id="migration74.new-features.core.tostring-exceptions">
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<title>Allow exceptions from __toString()</title>
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<para>
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Throwing exceptions from <link linkend="object.tostring">__toString()</link>
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is now permitted. Previously this resulted in a fatal error. Existing
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recoverable fatal errors in string conversions have been converted to
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<classname>Error</classname> exceptions.
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</para>
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</sect3>
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</sect2>
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<sect2 xml:id="migration74.new-features.curl">
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<title>CURL</title>
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<para>
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<classname>CURLFile</classname> now supports stream wrappers in addition
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to plain file names, if the extension has been built against libcurl >= 7.56.0.
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</para>
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</sect2>
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<sect2 xml:id="migration74.new-features.filter">
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<title>Filter</title>
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<para>
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The <constant>FILTER_VALIDATE_FLOAT</constant> filter now supports the
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<literal>min_range</literal> and <literal>max_range</literal>
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options, with the same semantics as <constant>FILTER_VALIDATE_INT</constant>.
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</para>
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</sect2>
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<sect2 xml:id="migration74.new-features.ffi">
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<title>FFI</title>
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<para>
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FFI is a new extension, which provides a simple way to call
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native functions, access native variables, and create/access
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data structures defined in C libraries.
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</para>
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</sect2>
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<sect2 xml:id="migration74.new-features.gd">
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<title>GD</title>
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<para>
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Added the <constant>IMG_FILTER_SCATTER</constant> image filter
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to apply a scatter filter to images.
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</para>
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</sect2>
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<sect2 xml:id="migration74.new-features.hash">
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<title>Hash</title>
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<para>
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Added <literal>crc32c</literal> hash using Castagnoli's polynomial.
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This CRC32 variant is used by storage systems, such as
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iSCSI, SCTP, Btrfs and ext4.
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</para>
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</sect2>
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<sect2 xml:id="migration74.new-features.mbstring">
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<title>Multibyte String</title>
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<para>
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Added the <function>mb_str_split</function> function, which provides
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the same functionality as <function>str_split</function>, but operating
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on code points rather than bytes.
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</para>
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</sect2>
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<sect2 xml:id="migration74.new-features.opcache">
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<title>OPcache</title>
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<para>
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<link linkend="opcache.preloading">Support for preloading code</link> has been added.
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</para>
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</sect2>
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<sect2 xml:id="migration74.new-features.pcre">
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<title>Regular Expressions (Perl-Compatible)</title>
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<para>
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The <function>preg_replace_callback</function> and <function>preg_replace_callback_array</function>
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functions now accept an additional <parameter>flags</parameter> argument, with support for the
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<constant>PREG_OFFSET_CAPTURE</constant> and <constant>PREG_UNMATCHED_AS_NULL</constant> flags.
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This influences the format of the matches array passed to the callback function.
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</para>
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</sect2>
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<sect2 xml:id="migration74.new-features.pdo">
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<title>PDO</title>
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<para>
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The username and password can now be specified as part of the PDO DSN for
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the mysql, mssql, sybase, dblib, firebird and oci drivers. Previously this
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was only supported by the pgsql driver. If a username/password is specified
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both in the constructor and the DSN, the constructor takes precedence.
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</para>
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<para>
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It is now possible to escape question marks in SQL queries to avoid them
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being interpreted as parameter placeholders. Writing <literal>??</literal>
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allows sending a single question mark to the database and e.g. use the
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PostgreSQL JSON key exists (<literal>?</literal>) operator.
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</para>
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</sect2>
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<sect2 xml:id="migration74.new-features.pdo_oci">
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<title>PDO_OCI</title>
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<para>
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<methodname>PDOStatement::getColumnMeta</methodname> is now available.
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</para>
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</sect2>
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<sect2 xml:id="migration74.new-features.pdo_sqlite">
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<title>PDO_SQLite</title>
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<para>
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<literal>PDOStatement::getAttribute(PDO::SQLITE_ATTR_READONLY_STATEMENT)</literal>
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allows checking whether the statement is read-only, i.e. if it doesn't modify
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the database.
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</para>
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<para>
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<literal>PDO::setAttribute(PDO::SQLITE_ATTR_EXTENDED_RESULT_CODES, true)</literal>
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enables the use of SQLite3 extended result codes in <function>PDO::errorInfo</function>
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and <function>PDOStatement::errorInfo</function>.
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</para>
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</sect2>
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<sect2 xml:id="migration74.new-features.sqlite3">
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<title>SQLite3</title>
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<para>
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Added <methodname>SQLite3::lastExtendedErrorCode</methodname>
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to fetch the last extended result code.
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</para>
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<para>
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Added <literal>SQLite3::enableExtendedResultCodes($enable = true)</literal>,
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which will make <methodname>SQLite3::lastErrorCode</methodname>
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return extended result codes.
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</para>
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</sect2>
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<sect2 xml:id="migration74.new-features.standard">
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<title>Standard</title>
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<sect3 xml:id="migration74.new-features.standard.strip-tags">
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<title>strip_tags() with array of tag names</title>
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<para>
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<function>strip_tags</function> now also accepts an array of allowed tags:
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instead of <literal>strip_tags($str, '<a><p>')</literal>
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you can now write <literal>strip_tags($str, ['a', 'p'])</literal>.
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</para>
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</sect3>
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<sect3 xml:id="migration74.new-features.standard.magic-serialize">
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<title>Custom object serialization</title>
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<para>
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A new mechanism for custom object serialization has been added, which
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uses two new magic methods: <literal>__serialize</literal>
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and <literal>__unserialize</literal>.
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<informalexample>
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<programlisting role="php">
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<![CDATA[
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<?php
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// Returns array containing all the necessary state of the object.
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public function __serialize(): array;
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// Restores the object state from the given data array.
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public function __unserialize(array $data): void;
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?>
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]]>
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</programlisting>
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</informalexample>
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The new serialization mechanism supersedes the
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<interfacename>Serializable</interfacename> interface,
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which will be deprecated in the future.
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</para>
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</sect3>
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<sect3 xml:id="migration74.new-features.standard.array-merge-no-args">
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<title>Array merge functions without arguments</title>
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<para>
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<function>array_merge</function> and <function>array_merge_recursive</function>
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may now be called without any arguments, in which case they will return an empty array.
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This is useful in conjunction with the spread operator, e.g. <literal>array_merge(...$arrays)</literal>.
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</para>
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</sect3>
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<sect3 xml:id="migration74.new-features.standard.proc-open">
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<title><function>proc_open</function> function</title>
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<para>
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<function>proc_open</function> now accepts an array instead of a
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string for the command. In this case the process will be opened
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directly (without going through a shell) and PHP will take care of
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any necessary argument escaping.
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<informalexample>
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<programlisting role="php">
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<![CDATA[
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<?php
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proc_open(['php', '-r', 'echo "Hello World\n";'], $descriptors, $pipes);
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?>
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]]>
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</programlisting>
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</informalexample>
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</para>
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<para>
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<function>proc_open</function> now supports
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<literal>redirect</literal> and <literal>null</literal> descriptors.
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<informalexample>
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<programlisting role="php">
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<![CDATA[
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<?php
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// Like 2>&1 on the shell
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proc_open($cmd, [1 => ['pipe', 'w'], 2 => ['redirect', 1]], $pipes);
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// Like 2>/dev/null or 2>nul on the shell
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proc_open($cmd, [1 => ['pipe', 'w'], 2 => ['null']], $pipes);
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?>
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]]>
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</programlisting>
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</informalexample>
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</para>
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</sect3>
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<sect3 xml:id="migration74.new-features.standard.sodium-argon-hash">
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<title>argon2i(d) without libargon</title>
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<para>
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<function>password_hash</function> now has the argon2i and argon2id implementations
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from the sodium extension when PHP is built without libargon.
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</para>
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</sect3>
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</sect2>
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</sect1>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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indent-tabs-mode:nil
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sgml-parent-document:nil
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sgml-default-dtd-file:"~/.phpdoc/manual.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:nil
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sgml-local-ecat-files:nil
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End:
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vim600: syn=xml fen fdm=syntax fdl=2 si
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vim: et tw=78 syn=sgml
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vi: ts=1 sw=1
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-->
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