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trigger_error

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

trigger_error — ユーザーレベルのエラー/警告/通知メッセージを生成する

説明

trigger_error(string $message, int $error_level = E_USER_NOTICE): bool

ユーザーエラーを発生させるために使います。組み込みのエラーハンドラまたは新しいエラーハンドラ (set_error_handler()) として設定済みのユーザー定義関数と組み合わせて使うこともできます。

この関数は、実行時の例外に特定の応答を生成する必要がある場合に便利です。

パラメータ

message: このエラーに割り当てられたメッセージ。長さは最大 1024 バイトまでです。1024 バイトを超える部分は切り捨てられます。
error_level: このエラーに割り当てられたエラー型です。E_USER 関連の定数のみが指定可能で、デフォルトは E_USER_NOTICE です。

戻り値

この関数は、間違った error_level が指定された場合に false を、それ以外の場合に true を返します。

例

例1 trigger_error() の例

より拡張した例については set_error_handler() を参照ください。

<?php
if ($divisor == 0) {
    trigger_error("ゼロで割ることはできません", E_USER_ERROR);
}
?>

注意

警告

message の HTML エンティティはエスケープされません。エラーをブラウザに表示するのであれば、メッセージに htmlentities() を使います。

参考

error_reporting() - 出力する PHP エラーの種類を設定する
set_error_handler() - ユーザー定義のエラーハンドラ関数を設定する
restore_error_handler() - 以前のエラーハンドラ関数を回復する
エラーレベル定数

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User Contributed Notes 5 notes

down

someone at attbi dot com ¶

20 years ago

the idea is never to give out file names, line numbers, and cryptic codes to the user. Use trigger_error() after you used set_error_handler() to register your own callback function which either logs or emails the error codes to you, and echo a simple friendly message to the user.



And turn on a more verbose error handler function when you need to debug your scripts. In my init.php scripts I always have:



if (_DEBUG_) {

    set_error_handler ('debug_error_handler');

}

else {

    set_error_handler ('nice_error_handler');

}

down

Howard Yeend ¶

14 years ago

trigger_error always reports the line and file that trigger_error was called on. Which isn't very useful.



eg:



main.php:

<?php

include('functions.php');

$x = 'test';

doFunction($x);

?>



functions.php:

<?php

function doFunction($var) {

if(is_numeric($var)) {

 /* do some stuff*/

} else {

 trigger_error('var must be numeric');

}

}

?>



will output "Notice: var must be numeric in functions.php on line 6"

whereas "Notice: var must be numeric in main.php on line 4" would be more useful



here's a function to do that:



<?php



function error($message, $level=E_USER_NOTICE) {

$caller = next(debug_backtrace());

trigger_error($message.' in <strong>'.$caller['function'].'</strong> called from <strong>'.$caller['file'].'</strong> on line <strong>'.$caller['line'].'</strong>'."\n<br />error handler", $level);

}

?>



So now in our example:



main.php:

<?php

include('functions.php');

$x = 'test';

doFunction($x);

?>



functions.php:

<?php

function doFunction($var) {

    if(is_numeric($var)) {

         /* do some stuff*/

    } else {

         error('var must be numeric');

    }

}



function error($message, $level=E_USER_NOTICE) {

    $caller = next(debug_backtrace());

    trigger_error($message.' in <strong>'.$caller['function'].'</strong> called from <strong>'.$caller['file'].'</strong> on line <strong>'.$caller['line'].'</strong>'."\n<br />error handler", $level);

}

?>



now outputs:



"Notice: var must be numeric in doFunction called from main.php on line 4"

down

richard at 2006 dot atterer dot net ¶

18 years ago

Beware, trigger_error() is absolutely useless for transporting your own function's error messages in $php_errormsg:

ini_set('track_errors', TRUE);
function x() { trigger_error('MY ERROR'); }
@x();
echo "Error 1: \\"$php_errormsg\\"\\n";
@file_get_contents('/nonexisting');
echo "Error 2: \\"$php_errormsg\\"\\n";

This outputs:

Error 1: ""
Error 2: "failed to open stream: No such file or directory"

This behaviour is consistent with the description of $php_errormsg, which says that the variable will only be available within the scope in which the error occurred. The problem can be worked around with a custom error handler like the one below. However, I'm undecided whether changing the language in this way is good:

function errHandler($errno, $errstr, $errfile, $errline) {
  global $php_errormsg; $php_errormsg = $errstr;
}
set_error_handler('errHandler');

down

aydin dot kn12 at gmail dot com ¶

9 years ago

If error_type is E_USER_ERROR then trigger_error throw FATAL ERROR and script stopped after this line.

<?php

$msg = 'This is the test message for echo';

trigger_error('Error message', E_USER_ERROR); // Script stopped after this line...

echo $msg; // This line does not appear...

?>

down

PhpMyCoder ¶

13 years ago

For those of you looking to use your own file or line number in the error (possibly using debug_backtrace()) instead of the ones created by trigger_error(), here is a solution:
Create a custom function to handle E_USER_ERRORs that simply outputs the error type and message, while excluding the line number and file trigger_error() reports. You may also configure it to handle user warnings and notices if necessary (I did in the example below).

<?php
function error_handler($level, $message, $file, $line, $context) {
    //Handle user errors, warnings, and notices ourself
    if($level === E_USER_ERROR || $level === E_USER_WARNING || $level === E_USER_NOTICE) {
        echo '<strong>Error:</strong> '.$message;
        return(true); //And prevent the PHP error handler from continuing
    }
    return(false); //Otherwise, use PHP's error handler
}

function trigger_my_error($message, $level) {
    //Get the caller of the calling function and details about it
    $callee = next(debug_backtrace());
    //Trigger appropriate error
    trigger_error($message.' in <strong>'.$callee['file'].'</strong> on line <strong>'.$callee['line'].'</strong>', $level);
}

//Use our custom handler
set_error_handler('error_handler');

//-------------------------------
//Demo usage:
//-------------------------------
function abc($str) {
    if(!is_string($str)) {
        trigger_my_error('abc() expects parameter 1 to be a string', E_USER_ERROR);
    }
}

abc('Hello world!'); //Works
abc(18); //Error: abc() expects parameter 1 to be a string in [FILE].php on line 31
?>

This is a pretty simple concept and I'm sure most of you know this, but for those that don't, let it serve as a good example!

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