简介

These are functions dealing with error handling and logging. They allow you to define your own error handling rules, as well as modify the way the errors can be logged. This allows you to change and enhance error reporting to suit your needs.

With the logging functions, you can send messages directly to other machines, to an email (or email to pager gateway!), to system logs, etc., so you can selectively log and monitor the most important parts of your applications and websites.

The error reporting functions allow you to customize what level and kind of error feedback is given, ranging from simple notices to customized functions returned during errors.

需求

无需外部库文件就可以加入本扩展模块的支持。

安装

这些函数作为 PHP 核心的一部分，无需被安装即可使用。

运行时配置

这些函数的行为受 php.ini 的影响。

以下是该配置选项的简要解释。

预定义常量

以下常量作为 PHP 核心的一部分一直有效。

The above values (either numerical or symbolic) are used to build up a bitmask that specifies which errors to report. You can use the bitwise operators to combine these values or mask out certain types of errors. Note that only '|', '~', '!', '^' and '&' will be understood within php.ini, however, and that no bitwise operators will be understood within php3.ini.

例

Below we can see an example of using the error handling capabilities in PHP. We define an error handling function which logs the information into a file (using an XML format), and e-mails the developer in case a critical error in the logic happens.

例子 1. Using error handling in a script <?php // we will do our own error handling error_reporting(0); // user defined error handling function function userErrorHandler($errno, $errmsg, $filename, $linenum, $vars) {     // timestamp for the error entry     $dt = date("Y-m-d H:i:s (T)");     // define an assoc array of error string     // in reality the only entries we should     // consider are E_WARNING, E_NOTICE, E_USER_ERROR,     // E_USER_WARNING and E_USER_NOTICE     $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          => "Runtime Notice"                 );     // set of errors for which a var trace will be saved     $user_errors = array(E_USER_ERROR, E_USER_WARNING, E_USER_NOTICE);          $err = "<errorentry>\n";     $err .= "\t<datetime>" . $dt . "</datetime>\n";     $err .= "\t<errornum>" . $errno . "</errornum>\n";     $err .= "\t<errortype>" . $errortype[$errno] . "</errortype>\n";     $err .= "\t<errormsg>" . $errmsg . "</errormsg>\n";     $err .= "\t<scriptname>" . $filename . "</scriptname>\n";     $err .= "\t<scriptlinenum>" . $linenum . "</scriptlinenum>\n";     if (in_array($errno, $user_errors)) {         $err .= "\t<vartrace>" . wddx_serialize_value($vars, "Variables") . "</vartrace>\n";     }     $err .= "</errorentry>\n\n";          // for testing     // echo $err;     // save to the error log, and e-mail me if there is a critical user error     error_log($err, 3, "/usr/local/php4/error.log");     if ($errno == E_USER_ERROR) {         mail("phpdev@example.com", "Critical User Error", $err);     } } function distance($vect1, $vect2) {     if (!is_array($vect1) || !is_array($vect2)) {         trigger_error("Incorrect parameters, arrays expected", E_USER_ERROR);         return NULL;     }     if (count($vect1) != count($vect2)) {         trigger_error("Vectors need to be of the same size", E_USER_ERROR);         return NULL;     }     for ($i=0; $i<count($vect1); $i++) {         $c1 = $vect1[$i]; $c2 = $vect2[$i];         $d = 0.0;         if (!is_numeric($c1)) {             trigger_error("Coordinate $i in vector 1 is not a number, using zero",                             E_USER_WARNING);             $c1 = 0.0;         }         if (!is_numeric($c2)) {             trigger_error("Coordinate $i in vector 2 is not a number, using zero",                             E_USER_WARNING);             $c2 = 0.0;         }         $d += $c2*$c2 - $c1*$c1;     }     return sqrt($d); } $old_error_handler = set_error_handler("userErrorHandler"); // undefined constant, generates a warning $t = I_AM_NOT_DEFINED; // define some "vectors" $a = array(2, 3, "foo"); $b = array(5.5, 4.3, -1.6); $c = array(1, -3); // generate a user error $t1 = distance($c, $b) . "\n"; // generate another user error $t2 = distance($b, "i am not an array") . "\n"; // generate a warning $t3 = distance($a, $b) . "\n"; ?>

参见

See also syslog().