Пропускать ошибки php

* the error handler that is set gets called regardless of what level the error reporting is set on, or whether the statement is preceeded with @

* it is up to the error handler to impart some meaning on the different error levels. You could make your custom error handler echo all errors, even if error reporting is set to NONE.

* so what does the @ operator do? It temporarily sets the error reporting level to 0 for that line. If that line triggers an error, the error handler will still be called, but it will be called with an error level of 0

Hope this helps someone

<?PHP(@include("file.php"))
OR die("Could not find file.php!");?>

This cause, that error reporting level is set to zero also for the included file. So if there are some errors in the included file, they will be not displayed.

So while yes, there is some overhead, per iteration, we see that the @ operator added only .005 ms per call. Not reason enough, imho, to avoid using the @ operator.

<?php

function x() { }

for ($i = 0; $i < 1000000; $i++) { x(); }

?>



real 0m7.617s

user 0m6.788s

sys 0m0.792s

vs

<?php

function x() { }

for ($i = 0; $i < 1000000; $i++) { @x(); }

?>



real 0m13.333s

user 0m12.437s

sys 0m0.836s

It is far better to test for the condition that you know will cause an error before preceding to run the code. This way only the error that you know about will be suppressed and not all future errors associated with that piece of code.

There may be a good reason for using outright error suppression in favor of the method I have suggested, however in the many years I've spent programming web apps I've yet to come across a situation where it was a good solution. The examples given on this manual page are certainly not situations where the error control operator should be used.

The following code will raise a Fatal error no matter what, and you wont be able to suppress it

<?phpfunction query()
{
$myrs = null;
$tmp = @$myrs->free_result();

return

$tmp;
}var_dump(query());

echo

"THIS IS NOT PRINT";
?>

more info at: https://bugs.php.net/bug.php?id=78532&thanks=3

It's a valid point that the @ operator hides all errors - so my rule of thumb is: use it only if you're aware of all possible errors your expression can throw AND you consider all of them irrelevant.

A simple example is
<?php

$x

= @$a["name"];?>
There are only 2 possible problems here: a missing variable or a missing index. If you're sure you're fine with both cases, you're good to go. And again: suppressing errors is not a crime. Not knowing when it's safe to suppress them is definitely worse.

@print($a);
is equivalent to
if isset($a) echo $a ;

@a++;
is equivalent to
if isset($a) $a++ ;
else $a = 1;

My PHP error settings are set to use E_ALL, and when I call error_reporting() from the error handler of a non-suppressed error, it returns E_ALL as expected.

But when an error occurs on an expression where I tried to suppress the error with the @ operator, it returns: E_ERROR | E_PARSE | E_CORE_ERROR | E_COMPILE_ERROR | E_USER_ERROR | E_RECOVERABLE_ERROR (or the number 4437).

I didn't want to use 4437 in my code in case it changes with different settings or future versions of PHP, so I now use:

<?php
function my_error_handler($err_no, $err_msg, $filename, $linenum) {
if (error_reporting() != E_ALL) {
return false; // Silenced
}// ...
}
?>

If the code needs to work with all versions of PHP, you could check that error_reporting() doesn't equal E_ALL or 0.

And, of course, if your error_reporting settings in PHP is something other than E_ALL, you'll have to change that to whatever setting you do use.

1. If you have set your own default error handler then the error still gets sent to the error handler regardless of the @ sign.

2. As mentioned below the @ suppression only changes the error level for that call. This is not to say that in your error handler you can check the given $errno for a value of 0 as the $errno will still refer to the TYPE(not the error level) of error e.g. E_WARNING or E_ERROR etc

3. The @ only changes the rumtime error reporting level just for that one call to 0. This means inside your custom error handler you can check the current runtime error_reporting level using error_reporting() (note that one must NOT pass any parameter to this function if you want to get the current value) and if its zero then you know that it has been suppressed.
<?php
// Custom error handler
function myErrorHandler($errno, $errstr, $errfile, $errline)
{
if ( 0 == error_reporting () ) {
// Error reporting is currently turned off or suppressed with @
return;
}
// Do your normal custom error reporting here
}
?>

For more info on setting a custom error handler see: http://php.net/manual/en/function.set-error-handler.php
For more info on error_reporting see: http://www.php.net/manual/en/function.error-reporting.php

So instead of :

<?phpfunction exception_error_handler($errno, $errstr, $errfile, $errline )
{
throw new ErrorException($errstr, 0, $errno, $errfile, $errline);
}set_error_handler("exception_error_handler");

function

catchException($e)
{
if (error_reporting() === 0)
{
return;
}// Do some stuff
}set_exception_handler('catchException');?>

It would be better to do :

<?phpfunction exception_error_handler($errno, $errstr, $errfile, $errline )
{
if (error_reporting() === 0)
{
return;
}

throw new

ErrorException($errstr, 0, $errno, $errfile, $errline);
}set_error_handler("exception_error_handler");

function

catchException($e)
{
// Do some stuff
}set_exception_handler('catchException');?>

<?php
// Tested: PHP 5.1.2 ~ 2006-10-13

// Typical Example

$var = @some_function();// Class/Object Example
$var = @new some_class();// Does NOT Work!
//$var = new @some_class(); // syntax error
?>

I found this most useful when connecting to a
database, where i wanted to control the errors
and warnings displayed to the client, while still
using the class style of access.

For example, a very reasonable use is to suppress the notice-level error generated by parse_ini_file() if you know the .ini file may be missing.
In my case getting the FALSE return value was enough to handle that situation, but I didn't want notice errors being output by my API.

TL;DR: Use it, but only if you know what you're suppressing and why.

Based on the following code, the result is NULL (but it would be nice if this were confirmed to be true in all cases).

<?php

$var

= 3;
$arr = array(); $var = @$arr['x']; // what is the value of $var after this assignment?

// is it its previous value (3) as if the assignment never took place?
// is it FALSE or NULL?
// is it some kind of exception or error message or error number?

var_dump($var); // prints "NULL"?>

>1. modify php.ini
>track_errors = On
>error_reporting = E_ALL & ~E_NOTICE
>2. Please note，if you already using customized error handler，it will prompt `undefined variable`
>please insert code`set_error_handler(null);` before executing code, e.g:
>```php
>set_error_handler(null);
>$my_file = @file ('phpinfo.phpx') or
>die ("<br>Failed opening file: <br>\t$php_errormsg");
>```

>(c)Kenny Fang

However there are rare cases in which notices and warnings are produced where the above behavour might be unproductive. Worse yet your error handling will kick out that exception before the function gets to return.

They are rare cases such as socket handling where certain states are expressed through errors causing ambiguity.

<?phpif (defined(PRODUCTION)) {
@function();
}
else {
function();
}?>

There could be something like this:

<?phpif (defined(PRODUCTION)) {
ini_set('error.silent',TRUE);
}
else {
ini_set('error.silent',FALSE);
}?>

However, typically if you want to set your own error handler, you would set the error_reporting to 0. Therefore, an alternative to detect the @ error suppression is required.

http://www.faqts.com/knowledge_base/view.phtml/aid/1/fid/40

It says "print can be used as part of a more complex expression where echo cannot".

Also, you can add multiple code to the result when an error occurs by separating each line with "and". Here is an example:

<?php
$my_file = @file ('non_existent_file') or print 'File not found.' and $string = ' Honest!' and print $string and $fp = fopen ('error_log.txt', 'wb+') and fwrite($fp, $string) and fclose($fp);
?>

A shame you can't use curly brackets above to enclose multiple lines of code, like you can with an if statement or a loop. It could make for a single long line of code. You could always call a function instead.