set_error_handler
(PHP 4 >= 4.0.1, PHP 5)
set_error_handler — Sets a user-defined error handler function
说明
mixed set_error_handler ( callback $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.
参数
- error_handler
-
The user function needs to accept two parameters: the error code, and a string describing the error. Then there are three optional parameters that may be supplied: the filename in which the error occurred, the line number in which the error occurred, and the context in which the error occurred (an array that points to the active symbol table at the point the error occurred). The function can be shown as:
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.
返回值
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.
更新日志
| 版本 | 说明 |
|---|---|
| 5.2.0 | The error handler must return FALSE to populate $php_errormsg. |
| 5.0.0 | The error_types parameter was introduced. |
| 4.3.0 | Instead of a function name, an array containing an object reference and a method name can also be supplied as the error_handler. |
| 4.0.2 | Three optional parameters for the error_handler user function was introduced. These are the filename, the line number, and the context. |
范例
Example #1 Error handling with set_error_handler() and trigger_error()
The example below shows the handling of internal exceptions by
triggering errors and handling them with a user defined function:
以上例程的输出类似于：
<?php
// error handler function
function myErrorHandler($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 />
";
echo " Fatal error on line $errline in file $errfile";
echo ", PHP " . PHP_VERSION . " (" . PHP_OS . ")<br />
";
echo "Aborting...<br />
";
exit(1);
break;
case E_USER_WARNING:
echo "<b>My WARNING</b> [$errno] $errstr<br />
";
break;
case E_USER_NOTICE:
echo "<b>My NOTICE</b> [$errno] $errstr<br />
";
break;
default:
echo "Unknown error type: [$errno] $errstr<br />
";
break;
}
return true;
}
// function to test the error handling
function scale_by_log($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
";
$a = array(2, 3, "foo", 5.5, 43.3, 21.11);
print_r($a);
// now generate second array
echo "----
vector b - a notice (b = log(PI) * a)
";
$b = scale_by_log($a, M_PI);
print_r($b);
// this is trouble, we pass a string instead of an array
echo "----
vector c - a warning
";
$c = scale_by_log("not array", 2.3);
var_dump($c); // NULL
// this is a critical error, log of zero or negative number is undefined
echo "----
vector d - fatal error
";
$d = scale_by_log($a, -2.5);
var_dump($d); // Never reached
?>
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
- ErrorException
- error_reporting() - Sets which PHP errors are reported
- restore_error_handler() - Restores the previous error handler function
- trigger_error() - Generates a user-level error/warning/notice message
- error level constants
- callback 类型的信息
