set_error_handler
set_error_handler
Sets a user-defined error handler function
**set_error_handler** $callback int $error_levels
Sets a user function () to handle
errors in a script.
callback
This function can be used to define custom error handlers during runtime,
for example in applications which need to do file/data cleanup when a critical
error happens, or when triggering an error in response to 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
unless the callback function returns false.
settings will have no effect and the
error handler will be called regardless - however, it's still possible to
read the current value of
and act
appropriately.
error_levels``error_reportingerror_reporting
Also note that it is the handler's responsibility to stop the
script's execution if necessary by calling . If the error-handler
function returns, script execution will continue with the next statement
after the one that caused an error.
exit
The following error types cannot be handled with a user defined
function: , ,
, ,
,
independent of where they were raised, and
most of raised in the file where
is called.
E_ERROR``E_PARSE``E_CORE_ERROR``E_CORE_WARNING``E_COMPILE_ERROR``E_COMPILE_WARNING``E_STRICT``set_error_handler
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.
callbackIf null is passed, the handler is reset to its default state.
Otherwise, the handler is a callback with the following signature:
```php
bool **** int $errno string $errstr string $errfile int $errline array $errcontext
`errno`
The first parameter, , will be passed the
level of the error raised, as an integer.
`errno`
`errstr`
The second parameter, , will be passed the
error message, as a string.
`errstr`
`errfile`
If the callback accepts a third parameter, ,
it will be passed the filename that the error was raised in, as a string.
`errfile`
`errline`
If the callback accepts a fourth parameter, ,
it will be passed the line number where the error was raised, as an integer.
`errline`
`errcontext`
If the callback accepts a fifth parameter, ,
it will be passed an array that points to the active symbol table at the
point the error occurred. In other words,
will contain an array of every variable that existed in the scope the
error was triggered in.
User error handlers must not modify the error context.
`errcontext``errcontext`
> **Waarschuwing:** > This parameter has been as of PHP 7.2.0,
> and as of PHP 8.0.0. If the function defines
> this parameter without a default, an error of "too few arguments" will be
> raised when it is called.
> *DEPRECATED**REMOVED*
If the function returns false then the normal error handler continues.
`error_levels`
Can be used to mask the triggering of the
function just like the ini setting
controls which errors are shown. Without this mask set the
will be called for every error
regardless to the setting of the setting.
`callback`error_reporting`callback`error_reporting
Returns the previously defined error handler (if any) as a .
If the built-in error handler is used null is returned.
`callable`
**Voorbeeld: Error handling with and **
The example below shows the handling of internal exceptions by
triggering errors and handling them with a user defined function:
```php
<?php
// error handler function
function myErrorHandler($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
?>
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 />
ErrorException``error_reporting``restore_error_handler``get_error_handler``trigger_errorerror level constants