set_error_handler

mixed set_error_handler ( callable $error_handler [, int $error_types = E_ALL | E_STRICT ] )

bool handler ( int $errno , string $errstr [, string $errfile [, int $errline [, array $errcontext ]]] )

<?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;
????}

????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);
????????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?"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 />