set_error_handler

(PHP 4 >= 4.0.1, PHP 5, PHP 7, PHP 8)

set_error_handler — 设置用户自定义的错误处理函数

说明

set_error_handler ( callable $error_handler , int $error_types = E_ALL | E_STRICT ) : mixed

设置用户的函数 (error_handler) 来处理脚本中出现的错误。

本函数可以用你自己定义的方式来处理运行中的错误， 例如，在应用程序中严重错误发生时，或者在特定条件下触发了一个错误(使用 trigger_error())，你需要对数据/文件做清理回收。

重要的是要记住 error_types 里指定的错误类型都会绕过 PHP 标准错误处理程序， 除非回调函数返回了 false。 error_reporting() 设置将不会起到作用而你的错误处理函数继续会被调用 —— 不过你仍然可以获取 error_reporting 的当前值，并做适当处理。 需要特别注意的是带 @ error-control operator 前缀的语句发生错误时，这个值会是 0。

同时注意，在需要时你有责任使用 die()。 如果错误处理程序返回了，脚本将会继续执行发生错误的后一行。

以下级别的错误不能由用户定义的函数来处理，独立于发生错误的地方： E_ERROR、 E_PARSE、 E_CORE_ERROR、 E_CORE_WARNING、 E_COMPILE_ERROR、 E_COMPILE_WARNING，和在 调用 set_error_handler() 函数所在文件中产生的大多数 E_STRICT。

如果错误发生在脚本执行之前（比如文件上传时），将不会 调用自定义的错误处理程序因为它尚未在那时注册。

参数

error_handler

以下格式的回调（callback）： 可以传入 null 重置处理程序到默认状态。 除了可以传入函数名，还可以传入引用对象和对象方法名的数组。

handler ( int $errno , string $errstr , string $errfile = ? , int $errline = ? , array $errcontext = ? ) : bool
errno
第一个参数 errno，包含了错误的级别，是一个 integer。
errstr
第二个参数 errstr，包含了错误的信息，是一个 string。
errfile
第三个参数是可选的，errfile， 包含了发生错误的文件名，是一个 string。
errline
第四个参数是一个可选项， errline， 包含了错误发生的行号，是一个 integer。
errcontext
第五个可选参数， errcontext， 是一个指向错误发生时活动符号表的 array。 也就是说，errcontext 会包含错误触发处作用域内所有变量的数组。 用户的错误处理程序不应该修改错误上下文（context）。
Warning

PHP 7.2.0 后此参数被弃用了。 极其不建议依赖它。

如果函数返回 false，标准错误处理处理程序将会继续调用。

error_types

就像error_reporting 的 ini 设置能够控制错误的显示一样， 此参数能够用于屏蔽 error_handler 的触发。 如果没有该掩码， 无论 error_reporting 是如何设置的， error_handler 都会在每个错误发生时被调用。

返回值

如果之前有定义过错误处理程序，则返回该程序名称的 string；如果是内置的错误处理程序，则返回 null。 如果你指定了一个无效的回调函数，同样会返回 null。 如果之前的错误处理程序是一个类的方法，此函数会返回一个带类和方法名的索引数组(indexed array)。

更新日志

版本 说明
7.2.0 errcontext 被废弃。 使用此参数时会导致 E_DEPRECATED 提醒。

范例

Example #1 用 set_error_handler() 和 trigger_error() 进行错误处理

以下示例展示了通过触发错误并以用户自定义的程序来进行内部异常的处理。

<?php
// error handler function
function myErrorHandler($errno, $errstr, $errfile, $errline)
{
    if (!(error_reporting() & $errno)) {
        // This error code is not included in error_reporting, so let it fall
        // through to the standard PHP error handler
        return false;
    }

    // $errstr may need to be escaped:
    $errstr = htmlspecialchars($errstr);

    switch ($errno) {
    case E_USER_ERROR:
        echo "<b>My ERROR</b> [$errno] $errstr<br />\n";
        echo "  Fatal error on line $errline in file $errfile";
        echo ", PHP " . PHP_VERSION . " (" . PHP_OS . ")<br />\n";
        echo "Aborting...<br />\n";
        exit(1);

    case E_USER_WARNING:
        echo "<b>My WARNING</b> [$errno] $errstr<br />\n";
        break;

    case E_USER_NOTICE:
        echo "<b>My NOTICE</b> [$errno] $errstr<br />\n";
        break;

    default:
        echo "Unknown error type: [$errno] $errstr<br />\n";
        break;
    }

    /* Don't execute PHP internal error handler */
    return true;
}

// function to test the error handling
function scale_by_log($vect, $scale)
{
    if (!is_numeric($scale) || $scale <= 0) {
        trigger_error("log(x) for x <= 0 is undefined, you used: scale = $scale", E_USER_ERROR);
    }

    if (!is_array($vect)) {
        trigger_error("Incorrect input vector, array of values expected", E_USER_WARNING);
        return null;
    }

    $temp = array();
    foreach($vect as $pos => $value) {
        if (!is_numeric($value)) {
            trigger_error("Value at position $pos is not a number, using 0 (zero)", E_USER_NOTICE);
            $value = 0;
        }
        $temp[$pos] = log($scale) * $value;
    }

    return $temp;
}

// set to the user defined error handler
$old_error_handler = set_error_handler("myErrorHandler");

// trigger some errors, first define a mixed array with a non-numeric item
echo "vector a\n";
$a = array(2, 3, "foo", 5.5, 43.3, 21.11);
print_r($a);

// now generate second array
echo "----\nvector b - a notice (b = log(PI) * a)\n";
/* Value at position $pos is not a number, using 0 (zero) */
$b = scale_by_log($a, M_PI);
print_r($b);

// this is trouble, we pass a string instead of an array
echo "----\nvector c - a warning\n";
/* Incorrect input vector, array of values expected */
$c = scale_by_log("not array", 2.3);
var_dump($c); // NULL

// this is a critical error, log of zero or negative number is undefined
echo "----\nvector d - fatal error\n";
/* log(x) for x <= 0 is undefined, you used: scale = $scale" */
$d = scale_by_log($a, -2.5);
var_dump($d); // Never reached
?>

以上例程的输出类似于：

vector a
Array
(
    [0] => 2
    [1] => 3
    [2] => foo
    [3] => 5.5
    [4] => 43.3
    [5] => 21.11
)
----
vector b - a notice (b = log(PI) * a)
<b>My NOTICE</b> [1024] Value at position 2 is not a number, using 0 (zero)<br />
Array
(
    [0] => 2.2894597716988
    [1] => 3.4341896575482
    [2] => 0
    [3] => 6.2960143721717
    [4] => 49.566804057279
    [5] => 24.165247890281
)
----
vector c - a warning
<b>My WARNING</b> [512] Incorrect input vector, array of values expected<br />
NULL
----
vector d - fatal error
<b>My ERROR</b> [256] log(x) for x <= 0 is undefined, you used: scale = -2.5<br />
  Fatal error on line 35 in file trigger_error.php, PHP 5.2.1 (FreeBSD)<br />
Aborting...<br />

参见

User Contributed Notes

Alex M 27-May-2021 11:37
If you are new to programming and you would like to know how to add a combination of those error reporting values to .htaccess file. Here's a small guide.

With PHP function error_reporting we can add together option with bitwise add operator | . But we can't use those constants in htaccess file and in my case I have no idea how to add bitwise number.

So, solution can be casting selected options to int:

echo (int)(E_ERROR | E_WARNING | E_PARSE | E_USER_ERROR) ;
->263

Then you can use 263 in .htaccess

php_value error_reporting 263

In my case I needed those errors to be displayed for my debugging server. But the combination can be different from mine.
David Spector 11-Oct-2020 01:02
The PHP manual is not very clear about how to handle @ operator error messages.

Here is working code:

    // Do nothing if @ operator
    $errLevel=error_reporting(E_ALL);
    if ($errLevel===0)
        return true; // ignore @ prefixed expression errors
a dot ross at amdev dot eu 20-Dec-2018 01:54
I'm missing a way to chain error handlers. It's not something offered by set_error_handler. You have to jump through some hoops to get it to work, but it *is* quite possible, by making use of the return value of the function. Here's an example:

<?
$previous = set_error_handler(function ($errno, $errstr, $errfile, $errline, $errcontext) use (&$previous) {
    /* Your custom error handling code here. */

    // If another error handler was defined, call it.
    if ($previous) {
        return $previous($errno, $errstr, $errfile, $errline, $errcontext);
    } else {
        // Use the standard PHP error handler.
        return false;
    }
});
?>
alvaro at demogracia dot com 12-Jun-2018 12:44
Don't forget that you can only have one active custom error handler:

<?php
set_error_handler(function($errno, $errstr){
    echo "Custom warning handler: $errstr", PHP_EOL;
}, E_WARNING);
set_error_handler(function($errno, $errstr){ // Overrides previous E_WARNING handler
    echo "Custom notice handler: $errstr", PHP_EOL;
}, E_NOTICE);

$foo++; // Custom notice handler: Undefined variable: foo
1/0; // Warning: Division by zero
?>
steve962 at gmail dot com 16-Mar-2018 04:06
Be careful when using the return value to this function.   Because it returns the old handler, you may be tempted to do something like:

<?php
function do_something()
    {
    $old = set_error_handler("my_error_handler");
    // Do something you want handled by my_error_handler
    set_error_handler($old);
    }
?>

This will work, but it will bite you because each time you do this, it will cause a memory leak as the old error handler is put on a stack for the restore_error_handler() function to use.

So always restore the old error handler using that function instead:

<?php
function do_something()
    {
    set_error_handler("my_error_handler");
    // Do something you want handled by my_error_handler
    restore_error_handler();
    }
?>
Klauss 12-Sep-2017 04:36
Hi everyone. I don't know if it is an old behavior of previous versions, but currently you can set exception and error handlers as private or protected methos, if, only if, you call `set_exception_handler()` or `set_error_handler()` within a context that can access the method.

Example:
    <?PHP
        $Handler = new class ()
        {
            public function __construct ()
            {
                set_error_handler([&$this, 'HandleError']);
                set_exception_handler([&$this, 'HandleException']);
            }
            protected function HandleError ( $Code, $Message, $File = null, $Line = 0, $Context = [] )
            {
                // Handle error here.
            }
            private function HandleException ( $Exception )
            {
                // Handle exception here.
            }
        }
    ?>

NOTE: these methods must match the callbacks parameters signatures.
chris at ocproducts dot com 04-Aug-2016 10:53
Note that error handlers don't run recursively. If you have an error while an error handler is running (in the error handler itself or code called from it) then you won't get the error handler called again.

This has subtle ramifications for $php_errormsg. If you are relying on your error handler to suppress certain kinds of error message from going into $php_errormsg (via return true; because error_reporting doesn't affect $php_errormsg setting) then this will not work for any code called within that error handler.
aditycse at gmail dot com 12-Jan-2016 07:36
<?php
/**
 * Used for logging all php notices,warings and etc in a file when error reporting
 * is set and display_errors is off
 * @uses used in prod env for logging all type of error of php code in a file for further debugging
 * and code performance
 * @author Aditya Mehrotra<[email protected]>
 */
error_reporting(E_ALL);
ini_set("display_errors", "off");
define('ERROR_LOG_FILE', '/var/www/error.log');

/**
 * Custom error handler
 * @param integer $code
 * @param string $description
 * @param string $file
 * @param interger $line
 * @param mixed $context
 * @return boolean
 */
function handleError($code, $description, $file = null, $line = null, $context = null) {
    $displayErrors = ini_get("display_errors");
    $displayErrors = strtolower($displayErrors);
    if (error_reporting() === 0 || $displayErrors === "on") {
        return false;
    }
    list($error, $log) = mapErrorCode($code);
    $data = array(
        'level' => $log,
        'code' => $code,
        'error' => $error,
        'description' => $description,
        'file' => $file,
        'line' => $line,
        'context' => $context,
        'path' => $file,
        'message' => $error . ' (' . $code . '): ' . $description . ' in [' . $file . ', line ' . $line . ']'
    );
    return fileLog($data);
}

/**
 * This method is used to write data in file
 * @param mixed $logData
 * @param string $fileName
 * @return boolean
 */
function fileLog($logData, $fileName = ERROR_LOG_FILE) {
    $fh = fopen($fileName, 'a+');
    if (is_array($logData)) {
        $logData = print_r($logData, 1);
    }
    $status = fwrite($fh, $logData);
    fclose($fh);
    return ($status) ? true : false;
}

/**
 * Map an error code into an Error word, and log location.
 *
 * @param int $code Error code to map
 * @return array Array of error word, and log location.
 */
function mapErrorCode($code) {
    $error = $log = null;
    switch ($code) {
        case E_PARSE:
        case E_ERROR:
        case E_CORE_ERROR:
        case E_COMPILE_ERROR:
        case E_USER_ERROR:
            $error = 'Fatal Error';
            $log = LOG_ERR;
            break;
        case E_WARNING:
        case E_USER_WARNING:
        case E_COMPILE_WARNING:
        case E_RECOVERABLE_ERROR:
            $error = 'Warning';
            $log = LOG_WARNING;
            break;
        case E_NOTICE:
        case E_USER_NOTICE:
            $error = 'Notice';
            $log = LOG_NOTICE;
            break;
        case E_STRICT:
            $error = 'Strict';
            $log = LOG_NOTICE;
            break;
        case E_DEPRECATED:
        case E_USER_DEPRECATED:
            $error = 'Deprecated';
            $log = LOG_NOTICE;
            break;
        default :
            break;
    }
    return array($error, $log);
}

//calling custom error handler
set_error_handler("handleError");

print_r($arra); //undefined variable
print_r($dssdfdfgg); //undefined variable
include_once 'file.php'; //No such file or directory
?>
dannykopping at gmail dot com 16-Feb-2014 09:52
Keep in mind that, when attempting to set a statically-defined error handler on a namespaced class in PHP >= 5.3, you need to use the class namespace:

<?php
set_error_handler('\\My\\Namespace\\Bob::errorHandler');
?>
jtrick77 at gmail dot com 30-Oct-2013 09:13
For anyone interested in the actual translated error codes and their meanings:

1    E_ERROR (integer)     Fatal run-time errors. These indicate errors that can not be recovered from, such as a memory allocation problem. Execution of the script is halted.    
2    E_WARNING (integer)     Run-time warnings (non-fatal errors). Execution of the script is not halted.    
4    E_PARSE (integer)     Compile-time parse errors. Parse errors should only be generated by the parser.    
8    E_NOTICE (integer)     Run-time notices. Indicate that the script encountered something that could indicate an error, but could also happen in the normal course of running a script.    
16    E_CORE_ERROR (integer)     Fatal errors that occur during PHP's initial startup. This is like an E_ERROR, except it is generated by the core of PHP.    
32    E_CORE_WARNING (integer)     Warnings (non-fatal errors) that occur during PHP's initial startup. This is like an E_WARNING, except it is generated by the core of PHP.    
64    E_COMPILE_ERROR (integer)     Fatal compile-time errors. This is like an E_ERROR, except it is generated by the Zend Scripting Engine.    
128    E_COMPILE_WARNING (integer)     Compile-time warnings (non-fatal errors). This is like an E_WARNING, except it is generated by the Zend Scripting Engine.    
256    E_USER_ERROR (integer)     User-generated error message. This is like an E_ERROR, except it is generated in PHP code by using the PHP function trigger_error().    
512    E_USER_WARNING (integer)     User-generated warning message. This is like an E_WARNING, except it is generated in PHP code by using the PHP function trigger_error().    
1024    E_USER_NOTICE (integer)     User-generated notice message. This is like an E_NOTICE, except it is generated in PHP code by using the PHP function trigger_error().    
2048    E_STRICT (integer)     Enable to have PHP suggest changes to your code which will ensure the best interoperability and forward compatibility of your code.    Since PHP 5 but not included in E_ALL until PHP 5.4.0
4096    E_RECOVERABLE_ERROR (integer)     Catchable fatal error. It indicates that a probably dangerous error occurred, but did not leave the Engine in an unstable state. If the error is not caught by a user defined handle (see also set_error_handler()), the application aborts as it was an E_ERROR.    Since PHP 5.2.0
8192    E_DEPRECATED (integer)     Run-time notices. Enable this to receive warnings about code that will not work in future versions.    Since PHP 5.3.0
16384    E_USER_DEPRECATED (integer)     User-generated warning message. This is like an E_DEPRECATED, except it is generated in PHP code by using the PHP function trigger_error().    Since PHP 5.3.0
32767    E_ALL (integer)     All errors and warnings, as supported, except of level E_STRICT prior to PHP 5.4.0.     32767 in PHP 5.4.x, 30719 in PHP 5.3.x, 6143 in PHP 5.2.x, 2047 previously

(Copied from http://php.net/manual/en/errorfunc.constants.php)
nicolas dot grekas+php at gmail dot com 23-Oct-2013 09:34
If you want to be sure that the native PHP error handler is called without resetting the handler stack (as set_error_handler(null) does), you can simply call set_error_handler with $error_types set to zero. This can be especially use full in conjunction with e.g. error_get_last():

<?php

// var_dump or anything else, as this will never be called because of the 0
set_error_handler('var_dump', 0);
@$undef_var;
restore_error_handler();

// error_get_last() is now in a well known state:
// Undefined variable: undef_var

... // Do something

$e = error_get_last();

...

?>
phil at propcom dot co dot uk 18-Sep-2013 08:38
It is important to note that the registered SPL autoloader will NOT be called if an E_STRICT error triggers the error handler which, in turn, tries to use classes which are not yet loaded.

In this instance, you should manually load classes required by the error handler.
elad dot yosifon at gmail dot com 01-Aug-2013 11:42
<?php
/**
 * throw exceptions based on E_* error types
 */
set_error_handler(function ($err_severity, $err_msg, $err_file, $err_line, array $err_context)
{
    // error was suppressed with the @-operator
    if (0 === error_reporting()) { return false;}
    switch($err_severity)
    {
        case E_ERROR:               throw new ErrorException            ($err_msg, 0, $err_severity, $err_file, $err_line);
        case E_WARNING:             throw new WarningException          ($err_msg, 0, $err_severity, $err_file, $err_line);
        case E_PARSE:               throw new ParseException            ($err_msg, 0, $err_severity, $err_file, $err_line);
        case E_NOTICE:              throw new NoticeException           ($err_msg, 0, $err_severity, $err_file, $err_line);
        case E_CORE_ERROR:          throw new CoreErrorException        ($err_msg, 0, $err_severity, $err_file, $err_line);
        case E_CORE_WARNING:        throw new CoreWarningException      ($err_msg, 0, $err_severity, $err_file, $err_line);
        case E_COMPILE_ERROR:       throw new CompileErrorException     ($err_msg, 0, $err_severity, $err_file, $err_line);
        case E_COMPILE_WARNING:     throw new CoreWarningException      ($err_msg, 0, $err_severity, $err_file, $err_line);
        case E_USER_ERROR:          throw new UserErrorException        ($err_msg, 0, $err_severity, $err_file, $err_line);
        case E_USER_WARNING:        throw new UserWarningException      ($err_msg, 0, $err_severity, $err_file, $err_line);
        case E_USER_NOTICE:         throw new UserNoticeException       ($err_msg, 0, $err_severity, $err_file, $err_line);
        case E_STRICT:              throw new StrictException           ($err_msg, 0, $err_severity, $err_file, $err_line);
        case E_RECOVERABLE_ERROR:   throw new RecoverableErrorException ($err_msg, 0, $err_severity, $err_file, $err_line);
        case E_DEPRECATED:          throw new DeprecatedException       ($err_msg, 0, $err_severity, $err_file, $err_line);
        case E_USER_DEPRECATED:     throw new UserDeprecatedException   ($err_msg, 0, $err_severity, $err_file, $err_line);
    }
});

class WarningException              extends ErrorException {}
class ParseException                extends ErrorException {}
class NoticeException               extends ErrorException {}
class CoreErrorException            extends ErrorException {}
class CoreWarningException          extends ErrorException {}
class CompileErrorException         extends ErrorException {}
class CompileWarningException       extends ErrorException {}
class UserErrorException            extends ErrorException {}
class UserWarningException          extends ErrorException {}
class UserNoticeException           extends ErrorException {}
class StrictException               extends ErrorException {}
class RecoverableErrorException     extends ErrorException {}
class DeprecatedException           extends ErrorException {}
class UserDeprecatedException       extends ErrorException {}
Jacob Slomp 04-Jun-2013 10:56
This might be handy if you don't want your clients to see the errors, and you do want to be one step ahead of them.

It emails you the errors even if it's a parse error.

set_error_handler() doesn't work for what I wanted.

<?php
ini_set('log_errors',TRUE);
ini_set('error_log','tiny_uploads/errors.txt');

if($_SERVER['REMOTE_ADDR'] != "YOUR IP ADDRESS"){
    ini_set('display_errors',false);
}
  
function byebye(){

        $dir = dirname(__FILE__);
        if(file_exists($dir."/tiny_uploads/errors.txt")){
       
            $errors = file_get_contents($dir."/tiny_uploads/errors.txt");
           
            if(trim($errors)){
           
                $head = "From: php_errors@".str_replace('www.','',$_SERVER['HTTP_HOST'])."\r\n";
               
                $errors .= "---------------------------------------------\n\n";
               
                $errors .= "\n\nServer Info:\n\n".print_r($_SERVER, 1)."\n\n";
                $errors .= "---------------------------------------------\n\n";
               
                $errors .= "\n\nCOOKIE:\n\n".print_r($_COOKIE, 1)."\n\n";
                $errors .= "---------------------------------------------\n\n";
               
                $errors .= "\n\nPOST:\n\n".print_r($_POST, 1)."\n\n";
                $errors .= "---------------------------------------------\n\n";
               
                $errors .= "\n\nGET:\n\n".print_r($_GET, 1)."\n\n";
               
               
                mail("[email protected]","PHP Error ".$_SERVER['HTTP_HOST']."", $errors , $head);
               
                $fp = fopen($dir."/tiny_uploads/errors.txt","w+");
                fputs($fp, "");
                fclose($fp);   
            }   
        }
}
register_shutdown_function("byebye");
?>
Philip 28-May-2013 07:10
By this function alone you can not catch fatal errors, there is a simple work around. Below is part of my error.php file which handles errors and exceptions in the application. Before someone complains I'll add that I do not care that I am using globals, this file is part of my mini framework and without the 'config' variable the application would crash anyways.

<?php

/**
 * Error handler, passes flow over the exception logger with new ErrorException.
 */
function log_error( $num, $str, $file, $line, $context = null )
{
    log_exception( new ErrorException( $str, 0, $num, $file, $line ) );
}

/**
 * Uncaught exception handler.
 */
function log_exception( Exception $e )
{
    global $config;
   
    if ( $config["debug"] == true )
    {
        print "<div style='text-align: center;'>";
        print "<h2 style='color: rgb(190, 50, 50);'>Exception Occured:</h2>";
        print "<table style='width: 800px; display: inline-block;'>";
        print "<tr style='background-color:rgb(230,230,230);'><th style='width: 80px;'>Type</th><td>" . get_class( $e ) . "</td></tr>";
        print "<tr style='background-color:rgb(240,240,240);'><th>Message</th><td>{$e->getMessage()}</td></tr>";
        print "<tr style='background-color:rgb(230,230,230);'><th>File</th><td>{$e->getFile()}</td></tr>";
        print "<tr style='background-color:rgb(240,240,240);'><th>Line</th><td>{$e->getLine()}</td></tr>";
        print "</table></div>";
    }
    else
    {
        $message = "Type: " . get_class( $e ) . "; Message: {$e->getMessage()}; File: {$e->getFile()}; Line: {$e->getLine()};";
        file_put_contents( $config["app_dir"] . "/tmp/logs/exceptions.log", $message . PHP_EOL, FILE_APPEND );
        header( "Location: {$config["error_page"]}" );
    }
   
    exit();
}

/**
 * Checks for a fatal error, work around for set_error_handler not working on fatal errors.
 */
function check_for_fatal()
{
    $error = error_get_last();
    if ( $error["type"] == E_ERROR )
        log_error( $error["type"], $error["message"], $error["file"], $error["line"] );
}

register_shutdown_function( "check_for_fatal" );
set_error_handler( "log_error" );
set_exception_handler( "log_exception" );
ini_set( "display_errors", "off" );
error_reporting( E_ALL );
dorphalsig at NOSPAMgmail dot com 06-Oct-2011 11:25
This actually works to catch Fatal errors...

<?php
function shutdown()
{
    $a=error_get_last();
    if($a==null)  
        echo "No errors";
    else
         print_r($a);
   
}
register_shutdown_function('shutdown');
ini_set('max_execution_time',1 );
sleep(3);
?>

it will output
Array ( [type] => 1 [message] => Maximum execution time of 1 second exceeded [file] => /path/to/file_name.php [line] => 136 )
francois vespa 22-Dec-2010 03:27
This is a note when using php from the terminal (the CLI interface). From the command line, even if you have some kind of error user handler function so STDERR will not display, fatal errors will still cause the PHP interpreter to display error text. There is nothing you can do about that php-wise. If using UNIX/Linux, you can add " 2>/dev/null" at the end of your command to force STDERR not to show
periklis 02-Aug-2010 08:09
How to handle fatal errors in php 5.2:

<?php
register_shutdown_function('shutdownFunction');
function shutDownFunction() {
    $error = error_get_last();
    if ($error['type'] == 1) {
        //do your stuff    
    }
}
?>
devermin at ti0n dot net 23-May-2010 03:46
At work I have some code with errors that uncatched are the causes of integrity loss (people calling web services with file_get_contents that fails silently and afterwards insert garbage in the database).

here is the solution I found to transform a specific set of errors into exception and afterwards be able to selectively act (with the error code) regarding categories : 

<?php
ini_set('error_reporting',E_ALL^E_NOTICE);

## first 10 bits reserved for the initial error number
define('EMASK',(~0)<<10);
define('ECODEMASK',~EMASK);
## categories
define('IOERROR', 1<<10);
define('EMPTYPARMS', 1<<11);
define('FAILURE', 1<<12);
## string error patterns => code

$catch_me=array(
    "/^(file_get_contents)\((.*)\).*failed to open stream: (.*)/ " =>
        array ( 'mesg' => "IO::Failed to open stream with",
                'code' => IOERROR | FAILURE
        ),
    "/^fopen\(.*\): Filename cannot be empty/" =>
        array( 'msg' => "Parameters::empty",
                'code' => EMPTYPARMS
        )
    );
function error_2_exception($errno, $errstr, $errfile, $errline,$context) {
    global $catch_me;
    foreach ($catch_me as $regexp  => $res) {
        if(preg_match($regexp,$errstr,$match)){
            throw new Exception($res['mesg'],$res['code']|( $errno & EMASK ) );
        }
    }
    /* switch back to PHP internal error handler  */
    return false;
}
## => want to catch this one
$f=file_get_contents("mlsdkfm");
## dont want to break existing wrong behaviour yet (so not caught)
$f=file_get_contents('');
## magic
set_error_handler("error_2_exception");
## behaviour remains the same
$f=file_get_contents('');
try {
## web services that dont work now raise an exception \o/
$f=file_get_contents("mlsdkfm");
} catch(Exception $e) {
## and I can group my exception by category
    echo ( $e->getCode() & FAILURE )  ? "\nEPIC FAIL\n" : "\nbegnine";
}

?>
kalle at meizo dot com 18-Dec-2009 06:11
This may be of help to someone, who is/was looking for a way to get a backtrace of fatal errors such as maximum memory allocation issues, which can not be handled with user-defined functions, to pin-point the problem:

On a server hosting many sites that share common PHP includes, I set in one spot:

<?php
@ini_set ("error_log", "/my/path/php.err-" . $_SERVER ["HTTP_HOST"] . "-" . $_SERVER ["REMOTE_ADDR"] . "-" . $_SERVER ["REQUEST_METHOD"] . "-" . str_replace ("/", "|", $_SERVER ["REQUEST_URI"]));
?>

I actually used some additional information too from my software that I omitted, but that way, you'll find errors sorted more neatly in for example:-

/my/path/php.err-website.com-127.0.0.1-GET-path|index.html?xyz

And that at least helped me tremendously to then further pin-point where the problem is, as opposed to before just seeing the out of memory and not knowing which site/page it was on (as the PHP error only contains the very latest PHP code where it ran out of memory, which usually is just a shared included file, not the actual page).
nizamgok at gmail dot com 15-Jun-2009 07:27
I have realized that a few people here mentioned that you cannot capture parse errors (type 4, E_PARSE). This is not true. Here is how I do. I hope this helps someone.

1) Create a "auto_prepend.php" file in the web root and add this:

<?php
register_shutdown_function('error_alert');

function error_alert()
{
        if(is_null($e = error_get_last()) === false)
        {
                mail('[email protected]', 'Error from auto_prepend', print_r($e, true));
        }
}
?>

2) Then add this "php_value auto_prepend_file /www/auto_prepend.php" to your .htaccess file in the web root.

* make sure you change the email address and the path to the file.
nsg 13-May-2009 04:58
If using E_USER_ERROR in conjunction with a custom error-handler, we are faced with an annoying choice:

If you choose to die() on such errors, __destruct()ors can still function, but we can't then return false and have the inbuilt handler log the error.

If you return false thus allowing the error to be logged, the script will halt, exit() style, and __destruct()'s won't happen.

It seems the only solutions in such a case is to a) log your own errors, or b) don't use E_USER_ERROR.
Marcelius 22-Jan-2009 05:41
Another way to catch PHP's fatal errors:

<?php
    error_reporting(E_ALL);
    ini_set('display_errors', 0);

    function shutdown(){
        $isError = false;
        if ($error = error_get_last()){
            switch($error['type']){
                case E_ERROR:
                case E_CORE_ERROR:
                case E_COMPILE_ERROR:
                case E_USER_ERROR:
                    $isError = true;
                    break;
            }
        }

        if ($isError){
            echo "Script execution halted ({$error['message']})";
        } else {
            echo "Script completed";
        }
    }

    register_shutdown_function('shutdown');
?>

Note that this will only catch runtime errors. So calling a method in a non existing class, or declaring a function twice does not trigger the shutdown handler.
wfinn at riverbed dot com 09-Jul-2008 06:15
"The following error types cannot be handled with a user defined function: E_ERROR, E_PARSE, E_CORE_ERROR, E_CORE_WARNING, E_COMPILE_ERROR, E_COMPILE_WARNING, and most of E_STRICT raised in the file where set_error_handler() is called."

This is not exactly true.  set_error_handler() can't handle them, but ob_start() can handle at least E_ERROR.

<?php

function error_handler($output)
{
    $error = error_get_last();
    $output = "";
    foreach ($error as $info => $string)
        $output .= "{$info}: {$string}\n";
    return $output;
}

ob_start('error_handler');

will_this_undefined_function_raise_an_error();

?>
webmaster at paramiliar dot com 03-Jan-2008 11:03
We needed to use an error handler to handle SQL errors while passing the query along so the query is also logged and this is what we came up with, its kind of an ugly bridge but it works 100%

<?php

function myErrorHandler($errno, $errstr, $errfile, $errline){
    switch ($errno) {
    case E_USER_ERROR:
        if ($errstr == "(SQL)"){
            // handling an sql error
            echo "<b>SQL Error</b> [$errno] " . SQLMESSAGE . "<br />\n";
            echo "Query : " . SQLQUERY . "<br />\n";
            echo "On line " . SQLERRORLINE . " in file " . SQLERRORFILE . " ";
            echo ", PHP " . PHP_VERSION . " (" . PHP_OS . ")<br />\n";
            echo "Aborting...<br />\n";
        } else {
            echo "<b>My ERROR</b> [$errno] $errstr<br />\n";
            echo "  Fatal error on line $errline in file $errfile";
            echo ", PHP " . PHP_VERSION . " (" . PHP_OS . ")<br />\n";
            echo "Aborting...<br />\n";
        }
        exit(1);
        break;

    case E_USER_WARNING:
    case E_USER_NOTICE:
    }
    /* Don't execute PHP internal error handler */
    return true;
}

// function to test the error handling

function sqlerrorhandler($ERROR, $QUERY, $PHPFILE, $LINE){
    define("SQLQUERY", $QUERY);
    define("SQLMESSAGE", $ERROR);
    define("SQLERRORLINE", $LINE);
    define("SQLERRORFILE", $PHPFILE);
    trigger_error("(SQL)", E_USER_ERROR);
}

set_error_handler("myErrorHandler");

// trigger an sql error
$query = "SELECT * FROM tbl LIMIT 1";
$sql = @mysql_query($query)
    or sqlerrorhandler("(".mysql_errno().") ".mysql_error(), $query, $_SERVER['PHP_SELF'], __LINE__);
   

?>
ash 04-Aug-2007 03:38
error handling function that handles both errors and exceptions; also features a backtrace including possible function arguments.

<?php

$cfg = array();
$cfg['debug'] = 1;
$cfg['adminEmail'] = '[email protected]';

function errorHandler($errno, $errstr='', $errfile='', $errline='')
{
    // if error has been supressed with an @
    if (error_reporting() == 0) {
        return;
    }

    global $cfg;

    // check if function has been called by an exception
    if(func_num_args() == 5) {
        // called by trigger_error()
        $exception = null;
        list($errno, $errstr, $errfile, $errline) = func_get_args();

        $backtrace = array_reverse(debug_backtrace());

    }else {
        // caught exception
        $exc = func_get_arg(0);
        $errno = $exc->getCode();
        $errstr = $exc->getMessage();
        $errfile = $exc->getFile();
        $errline = $exc->getLine();

        $backtrace = $exc->getTrace();
    }

    $errorType = array (
               E_ERROR            => 'ERROR',
               E_WARNING        => 'WARNING',
               E_PARSE          => 'PARSING ERROR',
               E_NOTICE         => 'NOTICE',
               E_CORE_ERROR     => 'CORE ERROR',
               E_CORE_WARNING   => 'CORE WARNING',
               E_COMPILE_ERROR  => 'COMPILE ERROR',
               E_COMPILE_WARNING => 'COMPILE WARNING',
               E_USER_ERROR     => 'USER ERROR',
               E_USER_WARNING   => 'USER WARNING',
               E_USER_NOTICE    => 'USER NOTICE',
               E_STRICT         => 'STRICT NOTICE',
               E_RECOVERABLE_ERROR  => 'RECOVERABLE ERROR'
               );

    // create error message
    if (array_key_exists($errno, $errorType)) {
        $err = $errorType[$errno];
    } else {
        $err = 'CAUGHT EXCEPTION';
    }

    $errMsg = "$err: $errstr in $errfile on line $errline";

    // start backtrace
    foreach ($backtrace as $v) {

        if (isset($v['class'])) {

            $trace = 'in class '.$v['class'].'::'.$v['function'].'(';

            if (isset($v['args'])) {
                $separator = '';

                foreach($v['args'] as $arg ) {
                    $trace .= "$separator".getArgument($arg);
                    $separator = ', ';
                }
            }
            $trace .= ')';
        }

        elseif (isset($v['function']) && empty($trace)) {
            $trace = 'in function '.$v['function'].'(';
            if (!empty($v['args'])) {

                $separator = '';

                foreach($v['args'] as $arg ) {
                    $trace .= "$separator".getArgument($arg);
                    $separator = ', ';
                }
            }
            $trace .= ')';
        }
    }

    // display error msg, if debug is enabled
    if($cfg['debug'] == 1) {
        echo '<h2>Debug Msg</h2>'.nl2br($errMsg).'<br />
            Trace: '.nl2br($trace).'<br />';
    }

    // what to do
    switch ($errno) {
        case E_NOTICE:
        case E_USER_NOTICE:
            return;
            break;

        default:
            if($cfg['debug'] == 0){
                // send email to admin
                if(!empty($cfg['adminEmail'])) {
                    @mail($cfg['adminEmail'],'critical error on '.$_SERVER['HTTP_HOST'], $errorText,
                            'From: Error Handler');
                }
                // end and display error msg
                exit(displayClientMessage());
            }
            else
                exit('<p>aborting.</p>');
            break;

    }

} // end of errorHandler()

function displayClientMessage()
{
    echo 'some html page with error message';

}

function getArgument($arg)
{
    switch (strtolower(gettype($arg))) {

        case 'string':
            return( '"'.str_replace( array("\n"), array(''), $arg ).'"' );

        case 'boolean':
            return (bool)$arg;

        case 'object':
            return 'object('.get_class($arg).')';

        case 'array':
            $ret = 'array(';
            $separtor = '';

            foreach ($arg as $k => $v) {
                $ret .= $separtor.getArgument($k).' => '.getArgument($v);
                $separtor = ', ';
            }
            $ret .= ')';

            return $ret;

        case 'resource':
            return 'resource('.get_resource_type($arg).')';

        default:
            return var_export($arg, true);
    }
}

?>
stepheneliotdewey at GmailDotCom 26-Jun-2007 08:48
The manual states:

"errcontext will contain an array of every variable that existed in the scope the error was triggered in. User error handler must not modify error context."

But do you know WHY you must not modify the error context? It appears that errcontext is (in effect if not literally) created by taking $GLOBALS and adding the non-global local variables as additional entries in that array, then passing the whole thing *by reference*.

(You can prove this to be true if you set up a custom error handler and then print_r($errcontext) within it, because $GLOBALS will be printed as a recursive array).

In other words, the language in the manual is misleading, because errcontext is NOT a copy of the variables that existed when the error WAS triggered, but rather is a reference to the *existing LIVE variables* in the calling script.

This includes superglobal variables like $_SERVER, $_POST, $_GET, etc., as well as all user-defined variables in scope.

The significance of that is that if you modify errcontext, you will be modifying those other variables, not just for the life of your error handling function, but for the life of the calling script as well.

That doesn't matter if you plan to halt execution in your error handling function, but it will lead to unexpected behavior if you modify $errcontext and then return to the program's normal flow after handling the error, because the variables will stay modified. For example, if you unset $_SERVER in your custom error handling function, it will remain unset once the function is over and you have returned to the page that generated the error.

This should be made clearer in the manual, starting by marking errhandler with an ampersand (&) for passage by reference in the "Parameters" section above, like so:

handler ( int $errno, string $errstr [, string $errfile [, int $errline [, array &$errcontext]]] )
gotrunko at hotmail dot com 20-Jun-2007 01:26
To ereg error in a text file

<?php
$log_file="log.txt";

set_error_handler(log_handler);

function log_handler ( $errno, $errstr,  $errfile, $errline, $errcontext )
{
    $context = var_export($errcontext, TRUE);
    log_error_ereg("errno:$errno ($errstr) file:$errfile, line:$errline, context:$context\n");
}

function log_error_ereg($mess)
{
    global $log_file;

    $fd = fopen($log_file, 'a');
    if(!$fd)
    {
        echo "<pre>$mess</pre>";
    }
    else
    {
        if(!fwrite($fd, date('Y-m-d H:i:s')." ERR : \n$mess\n\n"))
        {
            echo "<pre>$mess</pre>";
        }
        fclose($fd);
    }
}
?>
silkensedai at online dot fr 02-May-2007 12:37
i made an error handler that print also the backtrace and that can die on some errors. It can be useful if you want to die on every error you find.

<?php

function my_error_handler($errno, $errstr, $errfile, $errline){
    $errno = $errno & error_reporting();
    if($errno == 0) return;
    if(!defined('E_STRICT'))            define('E_STRICT', 2048);
    if(!defined('E_RECOVERABLE_ERROR')) define('E_RECOVERABLE_ERROR', 4096);
    print "<pre>\n<b>";
    switch($errno){
        case E_ERROR:               print "Error";                  break;
        case E_WARNING:             print "Warning";                break;
        case E_PARSE:               print "Parse Error";            break;
        case E_NOTICE:              print "Notice";                 break;
        case E_CORE_ERROR:          print "Core Error";             break;
        case E_CORE_WARNING:        print "Core Warning";           break;
        case E_COMPILE_ERROR:       print "Compile Error";          break;
        case E_COMPILE_WARNING:     print "Compile Warning";        break;
        case E_USER_ERROR:          print "User Error";             break;
        case E_USER_WARNING:        print "User Warning";           break;
        case E_USER_NOTICE:         print "User Notice";            break;
        case E_STRICT:              print "Strict Notice";          break;
        case E_RECOVERABLE_ERROR:   print "Recoverable Error";      break;
        default:                    print "Unknown error ($errno)"; break;
    }
    print ":</b> <i>$errstr</i> in <b>$errfile</b> on line <b>$errline</b>\n";
    if(function_exists('debug_backtrace')){
        //print "backtrace:\n";
        $backtrace = debug_backtrace();
        array_shift($backtrace);
        foreach($backtrace as $i=>$l){
            print "[$i] in function <b>{$l['class']}{$l['type']}{$l['function']}</b>";
            if($l['file']) print " in <b>{$l['file']}</b>";
            if($l['line']) print " on line <b>{$l['line']}</b>";
            print "\n";
        }
    }
    print "\n</pre>";
    if(isset($GLOBALS['error_fatal'])){
        if($GLOBALS['error_fatal'] & $errno) die('fatal');
    }
}

function error_fatal($mask = NULL){
    if(!is_null($mask)){
        $GLOBALS['error_fatal'] = $mask;
    }elseif(!isset($GLOBALS['die_on'])){
        $GLOBALS['error_fatal'] = 0;
    }
    return $GLOBALS['error_fatal'];
}

?>

Usage :

<?php
error_reporting(E_ALL);      // will report all errors
set_error_handler('my_error_handler');
error_fatal(E_ALL^E_NOTICE); // will die on any error except E_NOTICE
?>
alexey.kupershtokh.gmail 02-Oct-2006 12:07
2errd
I've got more convenient and safe error to exception converter:

class CustomException extends Exception {
  public static function errorHandlerCallback($code, $string, $file, $line, $context) {
    $e = new self($string, $code);
    $e->line = $line;
    $e->file = $file;
    throw $e;
  }
}
set_error_handler(array("CustomException", "errorHandlerCallback"), E_ALL);
errd 30-Jan-2006 05:52
In errors to exceptions conversion below I found some incorrect stuff. File and line properties of Exception point to line and file where Exception is thrown, but not where real error is occured.

Impoved errors to exceptions converting:
+ Fixed filename of exception handled
+ Fixed code line of exception handled

<?php

class CustomException extends Exception {
    public function setLine($line) { 
        $this->line=$line;
    }
    
    public function setFile($file) {
        $this->file=$file;
    }
}

function exceptionsHandler($code, $string, $file, $line) { 
    $exception=new CustomException($string, $code);
    $exception->setLine($line);
    $exception->setFile($file);
    throw $exception;
} 

set_error_handler('exceptionsHandler', E_ALL);

?>
24-Jan-2006 01:19
To honor the value of PHP's error_reporting() function, use:

<?
  if( ($level & error_reporting()) == 0 ) return;
?>
ia [AT] zoznam [DOT] sk 22-Sep-2005 04:33
as reply to dawiddr at gmail dot com:

Be careful with this when using __autoload(). When there is some error during parsing the file included in __autoload() so an exception is thrown, it results in following error:

Fatal error:  Function __autoload(ClassName) threw an exception of type 'Exception' in /network/webroot/dev/test.php on line 121

It is because exceptions can't be thrown in __autoload().
See __autoload() documentation (http://www.php.net/autoload) and bug #31102 (http://bugs.php.net/bug.php?id=31102&edit=3)
dawiddr at gmail dot com 05-Jul-2005 04:01
In PHP5, if you want to have exceptions thrown instead of normal errors - you could use an error handler, which throw exceptions:

<?php

function handler($errno, $errstr, $errfile, $errline)
{
    print "Error handled!\n";
    throw new Exception($errstr, $errno);
}

set_error_handler('handler');

try
{
    print 2 / 0; // simple error - division by zero
    print "This will never be printed";
}
catch (Exception $e)
{
    print "Exception catched:\n";
    print "Code: ".$e->getCode()."\n";
    print "Message: ".$e->getMessage()."\n";
    print "Line: ".$e->getLine();
}

?>

Result:

Error handled!
Exception catched:
Code: 2
Message: Division by zero
Line: 6

As you see, exception is catched like it have been thrown by division by zero - in try/catch clause. But line numer and backtrace shows, that is was thrown by the error handler.
Steffen Staehle 12-Jan-2005 02:29
Two notes on using set_error_handler() on behaviour that I noticed when migrating an application from php 4.2.1 to php 4.3.9 (I do not yet have php 5.0 available, this might not apply there!).

1. setting the system error handler

If you want to set the standard php error handler again, after having set your own error handler, this works in php 4.2.1 by passing in an empty string:

<?php

   function my_handler($log_level, $log_text, $error_file, $error_line)
   {
      // if an error occurs here, the standard error
      // would be called (to avoid recursion)

      // do something useful
      // ...
   }

   $last_handler = set_error_handler("my_handler");

   // after this, $last_handler == ""

   // restore standard error handler

   $last_handler = set_error_handler("");

   // after this, $last_handler == "my_handler"

?>

The very same code now raises an error in php 4.3.9:

   set_error_handler() expects argument 1, '', to be a valid callback

(Since the return value of the first call to set_error_handler() is still the empty string "", I don't see how this can be done any more. I don't really need this, because I use my own handlers as shown below, but it might be good to be aware of this.)

2. setting your own 'second level' handler

If you have set your own error handler, and want to replace it by another one (other than the standard php error handler) while it is being executed, note that the return value of set_error_handler when used INSIDE the error handler is "" instead of the name of the previous handler! This is not too surprising, because during execution of your self defined error handler, php replaces it with the standard php error handler to avoid infinite loops in case of problems inside the handler. This is only interesting if you want nested handlers as I do. Background of my design:

   1st level handler: log into DB
   2nd level handler: log into flat file (if log into DB fails)
   3rd level handler: print to stdout (if log into flat file fails) (this is the sytem handler, finally).

<?php

   function my_fallback_handler($log_level, $log_text, $error_file, $error_line)
   {
      // if an error occurs here, the standard error
      // would be called (to avoid recursion)

      // do something useful
      // ...

   } // my_fallback_handler

   function my_handler($log_level, $log_text, $error_file, $error_line)
   {
      // if an error occurs here, the standard error
      // would be called (to avoid recursion)

      // but we want to have a fallback handler different
      // to the standard error handler

      $last_handler = set_error_handler("my_fallback_handler");

      // I expected $last_handler == "my_handler"
      // (which it would outside my_handler())
      // but here it is the empty string ""

      // do something useful
      // ...

      // now set the 1st level handler again:
      // (do NOT use $last_handler as argument,
      // because it equals "")

      $last_handler = set_error_handler("my_handler");

   } // my_handler

   $last_handler = set_error_handler("my_handler");

?>
29-Mar-2004 04:13
It seems that when you're letting PHP know that you have a custom  error handler, you're not able to -update/set new- variables inside the class. Example:

<?php
class error {
   var $error;

   function error() {
       $this->setIni();    // this causes PHP to ignore all other changes to the class.
   }

   function handler() {
       echo $this->error.'!!';
   }

   function setText($text) {
         $this->error = $text;
   }

   function setIni() {
       set_error_handler(array($this, 'handler'));
   }
}

$eh = new error;
$eh->setText('Error! <br>');  // this will not be saved

trigger_error('text', E_USER_ERROR);
// prints '!!'
?>

How it should be done:
<?php
class error {
   var $error;

   function error() {
         // dont let PHP know of our error handler yet
   }

   function handler() {
       echo $this->error.'!!';
   }

   function setText($text) {
         $this->error = $text;
   }

   function setIni() {
       set_error_handler(array($this, 'handler'));
   }
}

$eh = new error;
$eh->setText('Error! <br>');  // this WILL work
$eh->setIni();  // call this method when you're ready with configuring the class. All other methods that will be called will have no effect on the errorHandling by PHP

trigger_error('text', E_USER_ERROR);
// prints 'Error! <br>!!'
?>
phpmanual at NO_SPHAMnetebb dot com 15-Nov-2003 08:19
Given this code:

class CallbackClass {
    function CallbackFunction() {
        // refers to $this
    }

    function StaticFunction() {
        // doesn't refer to $this
    }
}

function NonClassFunction() {
}

there appear to be 3 ways to set a callback function in PHP (using set_error_handler() as an example):

1: set_error_handler('NonClassFunction');

2: set_error_handler(array('CallbackClass', 'StaticFunction'));

3: $o =& new CallbackClass();
   set_error_handler(array($o, 'CallbackFunction'));

The following may also prove useful:

class CallbackClass {
    function CallbackClass() {
        set_error_handler(array(&$this, 'CallbackFunction')); // the & is important
    }
   
    function CallbackFunction() {
        // refers to $this
    }
}

The documentation is not clear in outlining these three examples.
mmtache at yahoo dot com 09-Feb-2003 01:06
The @ operator sets the error_reporting() value to 0.
This means you can use it with your own Error Handler too. for example:

function userErrorHandler($errno, $errmsg, $filename, $linenum, $vars) {
   if (error_reporting())
echo $errmsg;
    }
set_error_handler("userErrorHandler");

function test(){
trigger_error("Error Message", E_USER_WARNING);
}

@test(); // doesn't output anything
roy 12-Jun-2002 04:08
Useful thing to note - if your error handler throws an error in itself, PHP is smart enough to use the deault error handler to handle it. This way, you don't end up in infinite flaming loops of death. This seems to be true, at least, in PHP 4.2.

('Course, there are ways to create your handler to handle even this situation, but it's probably best left this way for general purposes.)