mirror of
https://github.com/sigmasternchen/php-doc-en
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git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@183650 c90b9560-bf6c-de11-be94-00142212c4b1
303 lines
10 KiB
XML
303 lines
10 KiB
XML
<?xml version="1.0" encoding="iso-8859-1"?>
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<!-- $Revision: 1.28 $ -->
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<!-- splitted from ./en/functions/errorfunc.xml, last change in rev 1.1 -->
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<refentry id="function.set-error-handler">
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<refnamediv>
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<refname>set_error_handler</refname>
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<refpurpose>
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Sets a user-defined error handler function
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</refpurpose>
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</refnamediv>
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<refsect1>
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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>callback</type><parameter>error_handler</parameter></methodparam>
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<methodparam choice="opt"><type>int</type><parameter>error_types</parameter></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. Returns a string containing the previously defined
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error handler (if any), or &false; on error. If the previous handler
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was a class method, this function will return an indexed array with
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the class and the method name.
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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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The second parameter <parameter>error_types</parameter> was introduced in
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PHP 5 and 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 controls
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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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<para>
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The user function needs to accept two parameters: the error code, and a
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string describing the error. From PHP 4.0.2, three optional
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parameters are supplied: the filename in which the error occurred, the
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line number in which the error occurred, and the context in which the
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error occurred (an array that points to the active symbol table at the
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point the error occurred). The function can be shown as:
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<methodsynopsis>
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<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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</simpara>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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<note>
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<simpara>
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Instead of a function name, an array containing an object reference and
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a method name can also be supplied. (Since PHP 4.3.0)
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</simpara>
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</note>
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<note>
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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>, 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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</note>
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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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<example>
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<title>
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Error handling with <function>set_error_handler</function> and
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<function>trigger_error</function>
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</title>
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<programlisting role="php">
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<![CDATA[
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<?php
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// set the error reporting level for this script
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error_reporting(E_USER_ERROR | E_USER_WARNING | E_USER_NOTICE);
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// error handler function
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function myErrorHandler($errno, $errstr, $errfile, $errline)
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{
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switch ($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 in line $errline of 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] $errstr<br />\n";
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break;
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default:
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echo "Unkown error type: [$errno] $errstr<br />\n";
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break;
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}
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}
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// function to test the error handling
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function scale_by_log($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 = $scale",
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E_USER_ERROR);
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}
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if (!is_array($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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for ($i=0; $i<count($vect); $i++) {
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if (!is_numeric($vect[$i]))
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trigger_error("Value at position $i is not a number, using 0 (zero)",
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E_USER_NOTICE);
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$temp[$i] = log($scale) * $vect[$i];
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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, generating a warning
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echo "----\nvector b - a warning (b = log(PI) * a)\n";
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$b = scale_by_log($a, M_PI);
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print_r($b);
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// this is trouble, we pass a string instead of an array
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echo "----\nvector c - an error\n";
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$c = scale_by_log("not array", 2.3);
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var_dump($c);
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// this is a critical error, log of zero or negative number is undefined
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echo "----\nvector d - fatal error\n";
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$d = scale_by_log($a, -2.5);
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?>
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]]>
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</programlisting>
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&example.outputs;
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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 warning (b = log(PI) * a)
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<b>WARNING</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 - an error
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<b>ERROR</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>FATAL</b> [256] log(x) for x <= 0 is undefined, you used: scale = -2.5<br />
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Fatal error in line 36 of file trigger_error.php, PHP 4.0.2 (Linux)<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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<para>
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It is important to remember that the standard PHP error handler is completely
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bypassed. <function>error_reporting</function> settings will have no effect
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and your error handler will be called regardless - however you are still
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able to read the current value of <link linkend="ini.error-reporting">error_reporting</link> and
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act 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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<note>
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<para>
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If errors occur before the script is executed (e.g. on file uploads) the custom
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error handler cannot be called since it is not registered at that time.
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</para>
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</note>
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<note>
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<para>
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The second parameter <parameter>error_types</parameter> was introduced
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in PHP 5.
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</para>
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</note>
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<para>
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See also <function>error_reporting</function>,
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<function>restore_error_handler</function>,
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<function>trigger_error</function>,
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<link linkend="errorfunc.constants">error level constants</link>,
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&listendand; &seealso.callback;.
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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:"../../../../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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