set_error_handler

说明

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. 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

返回值

Returns a string containing the previously defined error handler (if any), or FALSE on error. If the previous handler was a class method, this function will return an indexed array with the class and the method name.

更新日志

范例

例子 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 // set the error reporting level for this script error_reporting(E_USER_ERROR | E_USER_WARNING | E_USER_NOTICE); // error handler function function myErrorHandler($errno, $errstr, $errfile, $errline) {   switch ($errno) {   case E_USER_ERROR:     echo "<b>My ERROR</b> [$errno] $errstr<br />\n";     echo "  Fatal error in line $errline of 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] $errstr<br />\n";     break;   default:     echo "Unkown error type: [$errno] $errstr<br />\n";     break;   } } // function to test the error handling function scale_by_log($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;   }   for ($i=0; $i<count($vect); $i++) {     if (!is_numeric($vect[$i]))       trigger_error("Value at position $i is not a number, using 0 (zero)", E_USER_NOTICE);       $temp[$i] = log($scale) * $vect[$i];     }     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, generating a warning echo "----\nvector b - a warning (b = log(PI) * a)\n"; $b = scale_by_log($a, M_PI); print_r($b); // this is trouble, we pass a string instead of an array echo "----\nvector c - an error\n"; $c = scale_by_log("not array", 2.3); var_dump($c); // this is a critical error, log of zero or negative number is undefined echo "----\nvector d - fatal error\n"; $d = scale_by_log($a, -2.5); ?> 上例的输出类似于： vector a Array ( [0] => 2 [1] => 3 [2] => foo [3] => 5.5 [4] => 43.3 [5] => 21.11 ) ---- vector b - a warning (b = log(PI) * a) <b>WARNING</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 - an error <b>ERROR</b> [512] Incorrect input vector, array of values expected<br /> NULL ---- vector d - fatal error <b>FATAL</b> [256] log(x) for x <= 0 is undefined, you used: scale = -2.5<br /> Fatal error in line 36 of file trigger_error.php, PHP 4.0.2 (Linux)<br /> Aborting...<br />

参见