PHP prints call stack information

PHP prints the call stack information. an error occurs in PHP. We use set_error_handler for processing. if an exception occurs, use set_exception_handler. However, in debugging, we can also use

Debug_print_backtrace and debug_backtrace print the call stack information

Use of set_error_handler

 My ERROR [$errno] $errstr
\n";        echo "  Fatal error on line $errline in file $errfile";        echo ", PHP " . PHP_VERSION . " (" . PHP_OS . ")
\n";        echo "Aborting...
\n";        exit(1);        break;    case E_USER_WARNING:        echo "My WARNING [$errno] $errstr
\n";        break;    case E_USER_NOTICE:        echo "My NOTICE [$errno] $errstr
\n";        break;    default:        echo "Unknown error type: [$errno] $errstr
\n";        break;    }    /* Don't execute PHP internal error handler */    return true;}// function to test the error handlingfunction scale_by_log($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 $temp;}$old_error_handler = set_error_handler("myErrorHandler");?>

Use of set_exception_handler

 GetTrace (); foreach ($ trace as $ key => $ stackPoint) {// The Returned exception is similar, exception description $ trace [$ key] ['args '] = array_map ('gettype', $ trace [$ key] ['args']);} // format the exception information $ result = array (); foreach ($ trace as $ key => $ stackPoint) {$ result [] = sprintf ($ traceline, $ key, $ stackPoint ['file'], $ stackPoint ['line'], $ stackPoint ['function'], implode (',', $ stackPoint ['args']);} // trace always ends with {main} $ result [] = '#'. ++ $ Key. '{main}'; // write tracelines into main template $ msg = sprintf ($ msg, get_class ($ exception), $ exception-> getMessage (), $ exception-> getFile (), $ exception-> getLine (), implode ("\ n", $ result), $ exception-> getFile (), $ exception-> getLine (); error_log ($ msg) ;}?>