mirror of
https://github.com/sigmasternchen/php-doc-en
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0007fca77f
Patch by Sorin Nunca git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@349133 c90b9560-bf6c-de11-be94-00142212c4b1
385 lines
12 KiB
XML
385 lines
12 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<refentry xml:id="function.set-error-handler" xmlns="http://docbook.org/ns/docbook">
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<refnamediv>
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<refname>set_error_handler</refname>
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<refpurpose>Sets a user-defined error handler function</refpurpose>
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</refnamediv>
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<refsect1 role="description">
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&reftitle.description;
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<methodsynopsis>
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<type>mixed</type><methodname>set_error_handler</methodname>
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<methodparam><type>callable</type><parameter>error_handler</parameter></methodparam>
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<methodparam choice="opt"><type>int</type><parameter>error_types</parameter><initializer>E_ALL | E_STRICT</initializer></methodparam>
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</methodsynopsis>
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<para>
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Sets a user function (<parameter>error_handler</parameter>) to handle
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errors in a script.
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</para>
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<para>
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This function can be used for defining your own way of handling errors
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during runtime, for example in applications in which you need to do
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cleanup of data/files when a critical error happens, or when you need
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to trigger an error under certain conditions (using
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<function>trigger_error</function>).
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</para>
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<para>
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It is important to remember that the standard PHP error handler is completely
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bypassed for the error types specified by <parameter>error_types</parameter>
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unless the callback function returns &false;.
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<function>error_reporting</function> settings will have no effect and your
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error handler will be called regardless - however you are still able to read
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the current value of
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<link linkend="ini.error-reporting">error_reporting</link> and act
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appropriately. Of particular note is that this value will be 0 if the
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statement that caused the error was prepended by the
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<link linkend="language.operators.errorcontrol">@ error-control
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operator</link>.
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</para>
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<para>
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Also note that it is your responsibility to <function>die</function> if
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necessary. If the error-handler function returns, script execution
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will continue with the next statement after the one that caused an error.
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</para>
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<para>
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The following error types cannot be handled with a user defined
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function: <constant>E_ERROR</constant>, <constant>E_PARSE</constant>,
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<constant>E_CORE_ERROR</constant>, <constant>E_CORE_WARNING</constant>,
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<constant>E_COMPILE_ERROR</constant>,
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<constant>E_COMPILE_WARNING</constant> independent of where they were raised, and
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most of <constant>E_STRICT</constant> raised in the file where
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<function>set_error_handler</function> is called.
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</para>
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<para>
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If errors occur before the script is executed (e.g. on file uploads) the
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custom error handler cannot be called since it is not registered at that
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time.
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</para>
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</refsect1>
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<refsect1 role="parameters">
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&reftitle.parameters;
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<para>
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<variablelist>
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<varlistentry>
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<term><parameter>error_handler</parameter></term>
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<listitem>
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<para>
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A callback with the following signature.
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&null; may be passed instead, to reset this handler to its default state.
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Instead of a function name, an array containing an object reference
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and a method name can also be supplied.
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</para>
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<para>
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<methodsynopsis>
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<type>bool</type><methodname><replaceable>handler</replaceable></methodname>
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<methodparam><type>int</type><parameter>errno</parameter></methodparam>
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<methodparam><type>string</type><parameter>errstr</parameter></methodparam>
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<methodparam choice="opt"><type>string</type><parameter>errfile</parameter></methodparam>
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<methodparam choice="opt"><type>int</type><parameter>errline</parameter></methodparam>
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<methodparam choice="opt"><type>array</type><parameter>errcontext</parameter></methodparam>
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</methodsynopsis>
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<variablelist>
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<varlistentry>
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<term><parameter>errno</parameter></term>
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<listitem>
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<simpara>
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The first parameter, <parameter>errno</parameter>, contains the
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level of the error raised, as an integer.
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</simpara>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>errstr</parameter></term>
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<listitem>
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<simpara>
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The second parameter, <parameter>errstr</parameter>, contains the
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error message, as a string.
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</simpara>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>errfile</parameter></term>
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<listitem>
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<simpara>
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The third parameter is optional, <parameter>errfile</parameter>,
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which contains the filename that the error was raised in, as a string.
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</simpara>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>errline</parameter></term>
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<listitem>
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<simpara>
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The fourth parameter is optional, <parameter>errline</parameter>,
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which contains the line number the error was raised at, as an integer.
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</simpara>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>errcontext</parameter></term>
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<listitem>
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<simpara>
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The fifth parameter is optional, <parameter>errcontext</parameter>,
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which is an array that points to the active symbol table at the point
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the error occurred. In other words, <parameter>errcontext</parameter>
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will contain an array of every variable that existed in the scope the
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error was triggered in.
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User error handler must not modify error context.
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</simpara>
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<warning xmlns="http://docbook.org/ns/docbook">
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<simpara>
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This parameter has been <emphasis>DEPRECATED</emphasis> as of PHP 7.2.0.
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Relying on it is highly discouraged.
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</simpara>
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</warning>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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<para>
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If the function returns &false; then the normal error handler continues.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>error_types</parameter></term>
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<listitem>
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<para>
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Can be used to mask the triggering of the
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<parameter>error_handler</parameter> function just like the <link
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linkend="ini.error-reporting">error_reporting</link> ini setting
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controls which errors are shown. Without this mask set the
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<parameter>error_handler</parameter> will be called for every error
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regardless to the setting of the <link
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linkend="ini.error-reporting">error_reporting</link> setting.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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</refsect1>
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<refsect1 role="returnvalues">
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&reftitle.returnvalues;
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<para>
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Returns a string containing the previously defined error handler (if any). If
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the built-in error handler is used &null; is returned. &null; is also returned
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in case of an error such as an invalid callback. If the previous error handler
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was a class method, this function will return an indexed array with the class
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and the method name.
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</para>
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</refsect1>
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<refsect1 role="changelog">
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&reftitle.changelog;
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<para>
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<informaltable>
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<tgroup cols="2">
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<thead>
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<row>
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<entry>&Version;</entry>
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<entry>&Description;</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry>7.2.0</entry>
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<entry>
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<parameter>errcontext</parameter> became deprecated. Usage of this parameter now emits an <constant>E_DEPRECATED</constant> notice.
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</entry>
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</row>
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<row>
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<entry>5.5.0</entry>
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<entry>
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<parameter>error_handler</parameter> now accepts &null;.
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</entry>
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</row>
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<row>
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<entry>5.2.0</entry>
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<entry>
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The error handler must return &false; to populate
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<varname>$php_errormsg</varname>.
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</entry>
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</row>
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</tbody>
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</tgroup>
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</informaltable>
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</para>
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</refsect1>
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<refsect1 role="examples">
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&reftitle.examples;
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<para>
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<example>
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<title>Error handling with <function>set_error_handler</function> and <function>trigger_error</function></title>
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<para>
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The example below shows the handling of internal exceptions by
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triggering errors and handling them with a user defined function:
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</para>
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<programlisting role="php">
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<![CDATA[
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<?php
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// error handler function
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function myErrorHandler($errno, $errstr, $errfile, $errline)
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{
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if (!(error_reporting() & $errno)) {
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// This error code is not included in error_reporting, so let it fall
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// through to the standard PHP error handler
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return false;
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}
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switch ($errno) {
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case E_USER_ERROR:
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echo "<b>My ERROR</b> [$errno] $errstr<br />\n";
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echo " Fatal error on line $errline in file $errfile";
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echo ", PHP " . PHP_VERSION . " (" . PHP_OS . ")<br />\n";
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echo "Aborting...<br />\n";
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exit(1);
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break;
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case E_USER_WARNING:
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echo "<b>My WARNING</b> [$errno] $errstr<br />\n";
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break;
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case E_USER_NOTICE:
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echo "<b>My NOTICE</b> [$errno] $errstr<br />\n";
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break;
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default:
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echo "Unknown error type: [$errno] $errstr<br />\n";
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break;
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}
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/* Don't execute PHP internal error handler */
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return true;
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}
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// function to test the error handling
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function scale_by_log($vect, $scale)
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{
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if (!is_numeric($scale) || $scale <= 0) {
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trigger_error("log(x) for x <= 0 is undefined, you used: scale = $scale", E_USER_ERROR);
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}
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if (!is_array($vect)) {
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trigger_error("Incorrect input vector, array of values expected", E_USER_WARNING);
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return null;
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}
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$temp = array();
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foreach($vect as $pos => $value) {
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if (!is_numeric($value)) {
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trigger_error("Value at position $pos is not a number, using 0 (zero)", E_USER_NOTICE);
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$value = 0;
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}
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$temp[$pos] = log($scale) * $value;
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}
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return $temp;
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}
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// set to the user defined error handler
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$old_error_handler = set_error_handler("myErrorHandler");
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// trigger some errors, first define a mixed array with a non-numeric item
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echo "vector a\n";
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$a = array(2, 3, "foo", 5.5, 43.3, 21.11);
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print_r($a);
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// now generate second array
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echo "----\nvector b - a notice (b = log(PI) * a)\n";
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/* Value at position $pos is not a number, using 0 (zero) */
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$b = scale_by_log($a, M_PI);
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print_r($b);
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// this is trouble, we pass a string instead of an array
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echo "----\nvector c - a warning\n";
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/* Incorrect input vector, array of values expected */
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$c = scale_by_log("not array", 2.3);
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var_dump($c); // NULL
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// this is a critical error, log of zero or negative number is undefined
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echo "----\nvector d - fatal error\n";
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/* log(x) for x <= 0 is undefined, you used: scale = $scale" */
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$d = scale_by_log($a, -2.5);
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var_dump($d); // Never reached
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?>
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]]>
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</programlisting>
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&example.outputs.similar;
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<screen>
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<![CDATA[
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vector a
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Array
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(
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[0] => 2
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[1] => 3
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[2] => foo
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[3] => 5.5
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[4] => 43.3
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[5] => 21.11
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)
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----
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vector b - a notice (b = log(PI) * a)
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<b>My NOTICE</b> [1024] Value at position 2 is not a number, using 0 (zero)<br />
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Array
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(
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[0] => 2.2894597716988
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[1] => 3.4341896575482
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[2] => 0
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[3] => 6.2960143721717
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[4] => 49.566804057279
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[5] => 24.165247890281
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)
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----
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vector c - a warning
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<b>My WARNING</b> [512] Incorrect input vector, array of values expected<br />
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NULL
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----
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vector d - fatal error
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<b>My ERROR</b> [256] log(x) for x <= 0 is undefined, you used: scale = -2.5<br />
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Fatal error on line 35 in file trigger_error.php, PHP 5.2.1 (FreeBSD)<br />
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Aborting...<br />
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]]>
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</screen>
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</example>
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</para>
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</refsect1>
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<refsect1 role="seealso">
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&reftitle.seealso;
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<para>
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<simplelist>
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<member><classname>ErrorException</classname></member>
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<member><function>error_reporting</function></member>
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<member><function>restore_error_handler</function></member>
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<member><function>trigger_error</function></member>
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<member><link linkend="errorfunc.constants">error level constants</link></member>
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<member>&seealso.callback;</member>
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</simplelist>
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</para>
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</refsect1>
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</refentry>
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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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