set_error_handler

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

set_error_handler — Sets a user-defined error handler function

Description

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

Sets a user function (error_handler) to handle errors in a script.

This function can be used for defining your own way of handling errors during runtime, for example in applications in which you need to do cleanup of data/files when a critical error happens, or when you need to trigger an error under certain conditions (using trigger_error()).

It is important to remember that the standard PHP error handler is completely bypassed for the error types specified by error_types unless the callback function returns FALSE. error_reporting() settings will have no effect and your error handler will be called regardless - however you are still able to read the current value of error_reporting and act appropriately. Of particular note is that this value will be 0 if the statement that caused the error was prepended by the @ error-control operator.

Also note that it is your responsibility to die() if necessary. If the error-handler function returns, script execution will continue with the next statement after the one that caused an error.

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.

If errors occur before the script is executed (e.g. on file uploads) the custom error handler cannot be called since it is not registered at that time.

Parameters

error_handler

A callback with the following signature. NULL may be passed instead, to reset this handler to its default state. Instead of a function name, an array containing an object reference and a method name can also be supplied.

bool handler ( int $errno , string $errstr [, string $errfile [, int $errline [, array $errcontext ]]] )

errno: The first parameter, errno, contains the level of the error raised, as an integer.
errstr: The second parameter, errstr, contains the error message, as a string.
errfile: The third parameter is optional, errfile, which contains the filename that the error was raised in, as a string.
errline: The fourth parameter is optional, errline, which contains the line number the error was raised at, as an integer.
errcontext: The fifth parameter is optional, errcontext, which is an array that points to the active symbol table at the point the error occurred. In other words, 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.

If the function returns FALSE then the normal error handler continues.

error_types

Can be used to mask the triggering of the error_handler function just like the error_reporting ini setting controls which errors are shown. Without this mask set the error_handler will be called for every error regardless to the setting of the error_reporting setting.

Return Values

Returns a string containing the previously defined error handler (if any). If the built-in error handler is used NULL is returned. NULL is also returned in case of an error such as an invalid callback. If the previous error handler was a class method, this function will return an indexed array with the class and the method name.

Changelog

Version	Description
5.5.0	`error_handler` now accepts `NULL`.
5.2.0	The error handler must return `FALSE` to populate `$php_errormsg`.

Examples

Example #1 Error handling with set_error_handler() and trigger_error()

The example below shows the handling of internal exceptions by triggering errors and handling them with a user defined function:


<?php
// error handler function
function myErrorHandler($errno, $errstr, $errfile, $errline)
{
    if (!(error_reporting() & $errno)) {
        // This error code is not included in error_reporting
        return;
    }

    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);
        break;

    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
?>

The above example will output something similar to:

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 />

User Contributed Notes

Philip

2 years ago


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 );

elad dot yosifon at gmail dot com

2 years ago


<?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 {}

aditycse at gmail dot com

3 months ago


<?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<aditycse@gmail.com>
 */
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

2 years ago


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');
?>

kalle at meizo dot com

6 years ago


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).

silkensedai at online dot fr

9 years ago


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
?>

webmaster at paramiliar dot com

8 years ago


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__);
    

?>

wfinn at riverbed dot com

7 years ago


"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();

?>

phpmanual at NO_SPHAMnetebb dot com

12 years ago


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.

felix dot b at outlook dot com

11 months ago


I saw many checking for all the error constants manually in a switch statement. If you just want to add the type of the error (E_WARNING, E_NOTICE, etc) to your ErrorException, use array_search() with get_defined_constants():

new ErrorException("[" . array_search($errno, get_defined_constants(), true)  . "] " . $errstr, 0, $errno, $errfile, $errline);

stepheneliotdewey at GmailDotCom

8 years ago


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]]] )

francois vespa

5 years ago


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

devermin at ti0n dot net

5 years ago


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";

}



?>

Anonymous

10 years ago


To honor the value of PHP's error_reporting() function, use:

<?
  if( ($level & error_reporting()) == 0 ) return;
?>

eregon at eregon dot info

10 years ago


It is not possible to handle fatal errors with own handler. Even if you have set your own handler, fatal error will be always handled by PHP's default handler. The reason is the script may be in unstable state after fatal error occurence (details here: http://marc.theaimsgroup.com/?l=php-dev&m=97673386418430&w=2).

Steffen Staehle

11 years ago


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");

?>

sijmen at digitized dot nl

12 years ago


@jayp at groovejob dot com
As I said before, the reference operator doesn't have any effect on the the error handler. 

Proof of concepts:
http://trouby.digitized.nl/set_error_handler2.php
http://trouby.digitized.nl/set_error_handler2.php?source=1

Anonymous

12 years ago


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>!!'

?>

nicolas dot grekas+php at gmail dot com

2 years ago


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();

...

?>

periklis

5 years ago


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     

    } 

}

?>

Jacob Slomp

2 years ago


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("YOUR@EMAIL.COM","PHP Error ".$_SERVER['HTTP_HOST']."", $errors , $head);
                
                $fp = fopen($dir."/tiny_uploads/errors.txt","w+");
                fputs($fp, "");
                fclose($fp);    
            }    
        }
}
register_shutdown_function("byebye");
?>

dorphalsig at NOSPAMgmail dot com

4 years ago


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 )

mmtache at yahoo dot com

13 years ago


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

Fi Ras

11 months ago


This is my customized error handler : (excuse my english)

https://gist.github.com/anonymous/556c6c75daf83039b6f8/9c36020422a4be148a1f4df88a478526b985496e

jtrick77 at gmail dot com

2 years ago


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)

phil at propcom dot co dot uk

2 years ago


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.

contact [a] ionisis [.] com

5 years ago


There seems to be no way to access to access the _POST, _GET, etc if you call trigger_error from within a function inside a class file.

quickshiftin at gmail dot com

6 years ago


using the output_buffer as a way to trap fatal errors from php itself, like E_ERROR, cannot offer a complete solution, b/c output buffering is disabled on the cli since 4.3.5 ..

nsg

6 years ago


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

7 years ago


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.

jonbarnett at gmail dot com

8 years ago


Per the comment below:

There's no problem with static class functions.

The proper way to set a callback for a static class function is:

array("Classname", "functionname")

The class name is a string.  If you don't quote the string, PHP treats it as a barestring and triggers a notice.

/manual/en/language.pseudo-types.php

etienne at perval dot fr

8 years ago


Note that this function may return NULL in some cases, even when there are no errors.
For instance, this is the case when you call this function for the first time: the function returns NULL simply because there is no previous error handler defined.

ash

8 years ago


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'] = 'name@domain.tld';

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);
    }
}

?>

Thomas

8 years ago


Be careful with error-handlers if you are using require() with a function as argument, like
<?php 
  require(foo($foo));
?>
If the result of the function isn't a valid file to be included, you wont get any errormessage, but your script will crash without any output (see the bug-database for further details: http://bugs.php.net/bug.php?id=41862).

gotrunko at hotmail dot com

8 years ago


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);
    }
}
?>

greg sidberry[poetics5 at yahoo dot com]

8 years ago


I was using a class, and needed to have a function within it handle php errors. 

The following code will allow you to call a class function of already defined object while maintaining access to all the objects current data .
============================

set_error_handler("classPassPHPError");

$ObjectName="test";

$test->new className;

function classPassPHPError($errno, $errstr, $errfile, $errline){
global $ObjectName;

eval("global \$".$ObjectName.";");
eval("\$object=\$".$ObjectName.";");

$object->phpErrorHandler($errno, $errstr, $errfile, $errline);
$object=null;
}

mail at chernousov dot com

9 years ago


When fatal error occurs, class destructors are not executed.

<?

class someClass {
  function __construct() {
    echo '__construct()';
  }

  function __destruct() {
    echo '__destruct()';
  }
}

$someClass = new someClass();
someNonExistentFunction();

?>

Result will be:

__construct()
Fatal error: Call to undefined function someNonExistentFunction() in tes.php on line 14

alexey.kupershtokh.gmail

9 years ago


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);

jla

9 years ago


Other option to "handle" ALL errors

set_error_handler("yourHandler");

// Parse,Compile, Core, etc... Errors
ini_set('html_errors',false);
ini_set('error_prepend_string','<html><head><META http-equiv="refresh" content="0;URL=/error.php?msg=');
ini_set('error_append_string','"></head></html>');

docey

10 years ago


if you wan't to know the current error-handler
set use something like this:

$current_errorhandler = set_error_handler("myerrorhandler");
restore_error_handler();

this will set your custom error_handler and return
the name of the previous set error handler. by 
calling restore_error_handler, you remove your 
custom error_handler and set the error_handler that
was set back again.

this way you can also switch back to php-default error-handler 
without knowing how many error-handler already 
are set, by using a loop till an empty string is 
returned. because an empty string means 
"no error-handler set" wich means php's default 
errorhandler is set back. 

like in this code below:

function restore_phperrorhandler()
{
 // get current error handler.
 $previous_errorhandler = 
 set_error_handler("myerrorhandler");
 restore_error_handler();

 $max_loops = 20;
 $cur_loops = 0;
     
 // if current error handler is not already php's or fails.
    if(($previous_errorhandler != NULL) OR 
      ($previous_errorhandler != "")){
    
        while($previous_errorhandler != ""){
         $cur_loops = $cur_loops + 1;
             
            // check if not exceeding infinit loop.
            if($cur_loops >= $max_loops){
              trigger_error("Restoring exceeds max. loops.",
              E_USER_WARNING);
             return false;
            }
         
            //switch to previous handler.
            restore_error_handler();
         
            // get its name and switch to it again.
            $previous_errorhandler = 
            set_error_handler("myerrorhandler");
            restore_error_handler();
         
           // check if getting errorhandler failed.
           if($previous_errorhandler == NULL){
              trigger_error("Failed to get prev. error handler",
              E_USER_WARNING);
            return false;
             
            // empty string = php-default error handler
            }elseif($previous_errorhandler == ""){
             return true;
            }
        }
    }else{
      trigger_error("Current Error-Handler is default.",
      E_USER_NOTICE);
     return true;
    }
}

this function will loop and return true when no 
error handler is left. leaving php-default handler
in controll again. this is usefull if you want to
disable your own error-handler but be sure that
php's is handling your error's and not any other 
error-handler.

errd

10 years ago


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); 

?>

ia [AT] zoznam [DOT] sk

10 years ago


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)

frank at ethisoft dot nl

10 years ago


Perhaps it is worth mentioning that in 
PHP5 
both set_error_handler & set_exception_handler can be called with an array containing 2 arguments:
1) var  ==> object
2) string ==> name of handler function in object

EXAMPLE:
<?php
set_error_handler               (array($object, 'handler_function'));
set_exception_handler      (array($object, 'handler_function'));
?>

Both can point to the same object and handler_function so that both error and exception handling, which are very much alike usually, can be done by only 1 dedicated class.

Sukender

11 years ago


In PHP5, ou can ask for the default handler to be called after your custom handler by returning "false". See this pseudo-code :
<?
function MyHandler($errno, $errstr, $errfile, $errline, $errcontext) {
    my_handling_code;        // Do something, such as sending an email to the admin
    if (i_want_to_call_the_default_handler) return false;        // will invoke the default error handler just after
    else return true;        // This will NOT invoke it (= you've properly handled the error)
}
set_error_handler("MyHandler");
?>

I have not tested the functionality, but I think that the php.ini directive "log_errors" keeps working, but *only* when you call the default handler (= retrun false).

>>> Source : Mailing list thread about "re-invoking default error handler" at http://www.zend.com/lists/php-dev/200405/msg00491.html (be careful about the first post : "true" and "false" are switched - because it's only a proposition).

Joe

11 years ago


When a custom error handler is set, the php.ini directive "log_errors" stops working.  I'm guessing to favor your custom handler.  You can still log your errors with the "error_log" function, but it doesn't happen when you have a custom error handler.

Cezary Tomczak

12 years ago


Here is a script to debug / display errors in a nice way: http://gosu.pl/demo/ErrorHandler/ErrorHandler.zip

Example of displaying an error: http://gosu.pl/demo/ErrorHandler/example1.html
Example of displaying source of the file where the error appeared: http://gosu.pl/demo/ErrorHandler/example2.html

Displaying error: generates a backtrace, show file / line, show function / arguments (and values), source of the file

erwin at isiz dot nl

12 years ago


@sijmen at digitized dot nl
That's not true. The reference operator does have effect, when used correctly.

Your code doesn't use the reference operator in the set_error_handler function, but it does when creating the new error object. In your case, you have to use the reference operator two times.

When calling the set_error_handler function

<?php
        set_error_handler(array(&$this, 'handler'));
?>

and when creating the class

<?php
$eh = &new error;
?>

In that case the same error class will be used and the output will be following:
Error! 
!!

Hope this helps.

mightye (at) mightye (dot) org

12 years ago


You can't use this functionality to catch parse errors in included, required, or eval()'d code.  Parse errors seem to exist on a deeper level.

jayp at groovejob dot com

12 years ago


In response to sijmen at digitized dot nl:

Instead of 

$eh = new error;

use

$eh =& new error();

The new operator returns a copy of the error object, so the error handler that is set in the constructor is tied to a different object instance than the instance returned by "new".  To make sure you are working with the exact same object instance that you think you are, it's best to use the reference object when creating instances of objects, like so:

$oMyObject =& new MyObject();

HTH,

Jay

sijmen at digitized dot nl

12 years ago


@skyrl at free dot fr
It seems that the reference operator '&' doesn't have any effect. That's why I submitted the comment. 

<?php
class error {
    var $error;

    function error() {
        $this->setIni();
    }

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

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

    function setIni() {
        set_error_handler(array(&$this, 'handler')); // The '&' operator doesn't have any effect
    }
}

$eh = new error;
$eh->setText('Error! <br>'); // Will not get set

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

Proof of concept
http://trouby.digitized.nl/set_error_handler.php
http://trouby.digitized.nl/set_error_handler.php?source=1

skyrl at free dot fr

12 years ago


in reaction to the last '29-Mar-2004 11:13' post, just have to say that's normal the values are not "saved" in your error handler object. because the error object of the handler is not the same object as the one you instantiate...

You have to write set_error_handler(array(&this, 'my_error_handler')). The & is important for php to know that your error handler belongs to the same instance you allocate.

m0sh3 at hotmail dot com

8 years ago


Looks like there's no way to distinguish between catched exceptions thrown by internal classes and real warnings in custom error handlers:

<?php
function handleError($n, $m, $f, $l) {
    //no difference between excpetions and E_WARNING
    echo "user error handler: e_warning=".E_WARNING."  num=".$n." msg=".$m." line=".$l."\n";
    return true;
    //change to return false to make the "catch" block execute;
}
set_error_handler('handleError');
//turn off to make try/catch work normally

//uncomment this for a regular warning
timezone_open(1202229163);

//comment this whole try/catch out to see new DateTimeZone outside of a try / catch
//behavior is the same if you have set a custom error handler

//echo new DateTimeZone(1202229163);

//*
try {
    $z = new DateTimeZone(1202229163);
} catch (Exception $e) {
    echo "caught";
}
// */
?>

bob at db dot org

13 years ago


The documentation on this page kindly offers the following on using (class) methods as error handlers:

Note:  Instead of a function name, an array containing an object reference and a method name can also be supplied. (Since PHP 4.3.0)

Since that's all it says about the subject, I thought I'd offer a sample implementation to show how this can be used:

<?php

        class error {

                var $conf;
                var $lang;

                function error($conf, $lang) {
                        $this->conf = $conf;
                        $this->lang = $lang;

                        set_error_handler(array(&$this, 'handler'));
                }

                function handler($no, $str, $file, $line, $ctx) {
                        echo '<pre>';
                        echo 'no   : ' . $no . "\n";
                        echo 'str  : ' . $str . "\n";
                        echo 'file : ' . $file . "\n";
                        echo 'line : ' . $line . "\n";
                        echo 'ctx  : ';
                        print_r($ctx);
                        echo '</pre>';
                }

        }
?>

michal dot kocarek at NO_SPAM dot seznam dot cz

8 years ago


Be aware of efficiency and speed of your scripts!

If you use old-fashioned non-strict variable calling (example follows...), your custom error handler function degrades the script speed very big (especially for bigger projects). Because of for every "use of undefined constant" or "undefined variable" E_NOTICEs will be called your own custom error handler function.

<?
if ($form_variable) { ///< E_NOTICE Undefined variable
   // process form stuff
}
$foo[bar] = $const_array[baz]; ///< 2x E_NOTICE Use of undefined constant bar, baz

if (!$d) { // declare default $d ///< E_NOTICE Undefined variable
   $d = 5;
}
?>

As you can see in this poor example, badly writted scripts decrease the performace very big 'cause of the error handler is called almost everytime. So use custom-error-handler on heavily used pages only if you are writing scripts strictly. (Example follows:)
<?
if (isset($form_variable) && $form_variable != null) {
   // process form stuff
}
$foo['bar'] = $const_array['baz'];

if (!isset($d) || $d == null) {
   $d = 5;
}
?>

stepheneliotdewey at GmailDotCom

8 years ago


Additional note based on some further testing:

Although errcontext is effectively an array passed by reference to your custom error handling function, you cannot simply copy it over to another variable, because that variable will also act like a reference to errcontext, almost like an object.

Instead, the only way I can find to copy the errcontext array to a separate variable so that you can actually modify its values without changing the surrounding variable context, is to copy it piece-by-piece with a foreach loop. Not the most efficient way of working, but then again, errors are hopefully exceptional enough for you that performance will not be an overriding concern in this case.

roy

13 years ago


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.)

elven_rangers at yahoo dot com

9 years ago


Unfortunately, none of the procedures described here by other users to catch all errors work.

Then again this would be impossible as parse errors are triggered before the code is interpreted and executed so no code solution is possible (just as the documentation says).

You can test them easily against this simple code:

some_function_that_doesnt_exist();

using it in this form will trigger a Fatal Error (call to undefined function), which can't be caught by using your custom defined handler but *can* be caught by using the solutions presented by other programmers.

if you remove the ; from the end will trigger a Parse Error (syntax error), which *can't* be caught by any of these solutions. If this called is however places as the last line of code, just before the ?> then it will again generate a Fatal Error (call to undefined function).

if you further remove the () then you'll get a Notice (undefined constant) which can be caught by the manual method of defining a custom error handler.

ned at wgtech dot com

14 years ago


Just spent two days trying to find some method where a class can handle errors thrown at my convienience. After fighting with the pitfalls of this problem this is what I came up with. Hope it helps someone else save a little time. Its nice because all instances of this class will point to the same array that stores the errors.

class ApplicationObject {
    var $error_List;
    
    function ApplicationObject() {
        set_error_handler('trapError');
        $this->error_List = &trapError();
    }

}

function &trapError() {
    static $error_Vals = array();

    if (func_num_args()==5) { // Error Event has been passed
        $error_Vals[] = array(    'err_no' => func_get_arg(0), 'err_text' => func_get_arg(1), 'err_file' => func_get_arg(2), 'err_line' => func_get_arg(3), 'err_vars'=>func_get_arg(4));
    }
    if (func_num_args()==0) { // Setup call. Return reference
        return $error_Vals;
    }
}

kariedoo

9 years ago


function errorlog($type, $info, $file, $row)
{
   if ($handle = fopen("./log/ftp_error.log", "a")) 
   {
      @fwrite($handle, date("Y-m-d H:i:s")." "--> $type: $info FILE: $file -  Row $row\r\n" );
      @fclose($handle);
   }//end if
}//end function

### in the error logging code for example ftp: ###

set_error_handler("errorlog");  //set your own Handler
 
$this->connect = ftp_connect(TXTCONNECT);
$this->login = ftp_login($this->connect, TXTID, FTPPASS);
$this->systype= ftp_systype($this->connect);

restore_error_handler(); //restore the old handler

------------------
content in file
------------------

2006-05-08 09:36:02 2: ftp_login(): Login incorrect. FILE: /html/cgi-bin/test/classes/ftp.class.php - Row 63

Gulopine

10 years ago


Also note that even though the documentation states "errcontext will contain an array of every variable that existed in the scope the error was triggered in," that is not the case for $this in an instantiated object, as of PHP 5.1.1.

<?php

function error_function($errno, $errstr, $errfile, $errline, $errcontext) {
    print_r($errcontext);
}

set_error_handler('error_function');

class test_class {
    private $id;
    
    function __construct($id) {
        $this->id = $id;
        trigger_error('Test error');
    }
}

$test = new test_class(5);

?>

Result:

Array
(
    [id] => 5
)

I discovered this when trying to write an error handler that would log the class the error occured in, as it was triggered from a function in a parent class extended by several individual classes.

dawiddr at gmail dot com

10 years ago


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.

jgiglio at netmar dot com

11 years ago


set_error_handler also overrides the default behavior of postgresql which is to shoot HTML errors to the browser on a query failure or other database error.

I can't find a list of symbolic $errno names for postgres errors, but a normal "bad query" throws an errno of 2.

Be careful to not use an empty default case in your errno case statement if you use postgresql, and expect php to generate DB errors automatically.

Thomas Staunton

13 years ago


The best way, I have found to use a class/object as an error handler is to define a class, add your desired error handling function into the constructor and then call set_error_handler() to the name of your function, thats it. e.g. 

Class Error {

  Function Error() {
    Function HandleError($n, $m, $f, $l){
      print_r(debug_backtrace());
    }
    set_error_handler('HandleError');
  }
}

publicmail at macfreek dot nl

13 years ago


Note: If you have a custom error handler and use assert(), you MUST set:

assert_options (ASSERT_WARNING, 0);

Otherwise, no output whatsoever will ever be shown if an assert fails.

yvan.burrie

1 year ago


Here's a way to customize error messages for each function or functions within classes:

<?php

// This lists all error messages from each function including functions contained within classes and their associated scope:
$_ERRORS [ 'errorTest::makeError1' ]= 'Attempting to make an error' ;
$_ERRORS [ 'errorTest->makeError2' ]= 'Attempting to make another error' ;
$_ERRORS [ 'strpos' ]                = 'Failed to find offset of data from string' ;
$_ERRORS [ 'strlen' ]                = 'Failed to calculate length of string' ;
$_ERRORS [ 'substr' ]                = 'Failed to retrieve data from string' ;
$_ERRORS [ 'pack' ]                    = 'Failed to export binary package' ;
$_ERRORS [ 'unpack' ]                = 'Failed to import binary package' ;
$_ERRORS [ 'number_format' ]        = 'Failed to represent numeracy as number' ;
$_ERRORS [ 'implode' ]                = 'Failed to implode array elements' ;
$_ERRORS [ 'explode' ]                = 'Failed to explode array elements' ;
$_ERRORS [ 'fopen' ]                = 'Failed to initialize stream opening' ;
$_ERRORS [ 'fread' ]                = 'Failed to extract data from stream' ;
$_ERRORS [ 'fwrite' ]                = 'Failed to retract data into stream' ;
$_ERRORS [ 'fseek' ]                = 'Failed to seek offset from stream' ;
$_ERRORS [ 'rewind' ]                = 'Failed to rewind offset from stream' ;
$_ERRORS [ 'ftell' ]                = 'Failed to retrieve offset from stream' ;
$_ERRORS [ 'file_get_contents' ]    = 'Failed to retrieve contents from file' ;
$_ERRORS [ 'file_put_contents' ]    = 'Failed to conduct contents into file' ;
$_ERRORS [ 'stream_get_contents' ]    = 'Failed to retrieve contents from stream' ;
$_ERRORS [ 'call_user_func_array' ]    = 'Failed to call function with array' ;
$_ERRORS [ 'max' ]                    = 'Failed to retrieve maximum elements' ;
$_ERRORS [ 'min' ]                    = 'Failed to retrieve minimum elements' ;
$_ERRORS [ 'array_chunk' ]            = 'Failed to retrieve chunks of array elements' ;
$_ERRORS [ 'array_combine' ]        = 'Failed to combine keys for array elements' ;
$_ERRORS [ 'array_diff' ]            =
$_ERRORS [ 'array_diff_assoc' ]        =
$_ERRORS [ 'array_diff_key' ]        =
$_ERRORS [ 'array_diff_uassoc' ]    =
$_ERRORS [ 'array_diff_ukey' ]        = 'Failed to differentiate array elements' ;
$_ERRORS [ 'array_fill' ]            =
$_ERRORS [ 'array_fill_keys' ]        = 'Failed to allocate array elements' ;
$_ERRORS [ 'array_flip' ]            = 'Failed to flip array elements to keys' ;
//$_ERRORS [ 'array_slice' ]            = 'Failed to slice array elements' ;

/**
 *  
 */
set_error_handler
(
    function ( $code , $text , $file , $line , array $cont ) use ( $_ERRORS )
    {
        if ( error_reporting () )
        {
            $result = [] ;
            foreach ( debug_backtrace () as $detail )
            {
                $string = @ $_ERRORS [ @ $detail [ 'class' ] . @ $detail [ 'type' ] . @ $detail [ 'function' ] ] ;
                if ( isset ( $string ) )
                {
                    $result [] = $string ;
                }
            }
            if ( count ( $result ) )
            {
                $result = implode ( ': ' , array_reverse ( $result ) ) . '.' ;
            }
            else
            {
                $result = 'Undefined procedural behaviour' ;
            }
            throw new ErrorException ( $result , $code , 0 , $file , $line ) ;
        }
    } ,
    E_ALL | E_STRICT
) ;

// Examples :

class errorTest
{
    static function makeError1 ()
    {
        strpos () ;
    }

    public function makeError2 ()
    {
        strlen () ;
    }
}

$err = new errorTest ;

try
{
    substr () ;
}
catch ( Exception $E )
{
    echo $E -> getMessage () . "\n" ;
}

try
{
    errorTest :: makeError1 () ;
}
catch ( Exception $E )
{
    echo $E -> getMessage () . "\n" ;
}

try
{
    $err -> makeError2 () ;
}
catch ( Exception $E )
{
    echo $E -> getMessage () . "\n" ;
}

try
{
    // this function was not listed in the $_ERRORS variable and will therefore view the default message
    array_slice () ;
}
catch ( Exception $E )
{
    echo $E -> getMessage () . "\n" ;
}

/*
The above examples will output:

    Failed to retrieve data from string.
    Attempting to make an error: Failed to find offset of data from string.
    Attempting to make another error: Failed to calculate length of string.
    Undefined procedural behaviour
*/
?>

nizamgok at gmail dot com

6 years ago


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('your.email@example.com', '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.

dk at brightbyte dot de

9 years ago


Sometimes, you want to "catch" only some errors, and let the default handler deal with the result. I just found out that (at least in PHP 5), the default handler will be called if you return false (not 0 or NULL or '', but false) from your custom handler. This allows for "chaining" handlers.

The fature was suggested in this thread:
http://www.zend.com/lists/php-dev/200405/msg00491.html - the initial suggestion was to call the default handler if true is returned, but this was changed later on, apperently.

florian at siweho dot de

10 years ago


@ mmtache at yahoo dot com
you have to use
if(error_reporting() != 0){
   .... (yourOwnHandler)

instead of
if(error_reporting()){
   ....

in PHP5. then operations like this "@fopen" won't show an error-message

419472477 at qq dot com

1 year ago


<html>
<head><title>自定义错误</title></head>
自定义错误函数：<br>
<form action='index.php' method='post'>
<select name='kind'> 
<option value='E_WARNING'>E_WARNING</option>
<option value='E_NOTICE'>E_NOTICE</option>
<option value='E_USER_ERROR'>E_USER_ERROR</option>
<option value='E_USER_WARNING'>E_USER_WARNING</option>
<option value='E_USER_NOTICE'>E_USER_NOTICE</option>
</select>
<input type='submit' value='测试自定义错误函数'>
</form>
</html>
<?php
//自定义错误函数：
set_error_handler('a',E_WARNING);
set_error_handler('b',E_NOTICE);
set_error_handler('c',E_USER_ERROR);
set_error_handler('d',E_USER_WARNING);
set_error_handler('e',E_USER_NOTICE);
$x=$_REQUEST['kind'];
switch($x)
{
    case 'E_WARNING':trigger_error('这是自定义错误函数E_WARNING:',E_WARNING);break;
    case 'E_NOTICE':trigger_error('这是自定义错误函数E_NOTICE:',E_NOTICE);break;
    case 'E_USER_ERROR':trigger_error('这是自定义错误函数E_USER_ERROR:',E_USER_ERROR);break;
    case 'E_USER_WARNING':trigger_error('这是自定义错误函数E_USER_WARNING:',E_USER_WARNING);break;
    case 'E_USER_NOTICE':trigger_error('这是自定义错误函数E_USER_NOTICE:',E_USER_NOTICE);break;
    default: echo '请选择支持的错误';break;
}

//错误函数：
function a($errno,$errstr){echo '我就是自定义错误函数E_WARNING'.$errno;}
function b($errno,$errstr){echo '我就是E_NOTICE自定义错误函数'.$errno;}
function c($errno,$errstr){echo '我就是E_USER_ERROR自定义错误函数'.$errno;}
function d($errno,$errstr){echo '我就是E_USER_WARNING自定义错误函数'.$errno;}
function e($errno,$errstr){echo '我就是E_USER_NOTICE自定义错误函数'.$errno;}
?>
完整的set_error_handler与trigger_error使用。
保存为php文件浏览器访问即可见到效果

set_error_handler

Description

Parameters

Return Values

Changelog

Examples

See Also

User Contributed Notes