Divide by Zero warning is not caught in a PHP try/catch block

Question

I have this PHP code. Whenever y becomes zero, it shows a warning instead of catching the exception. Is there anything wrong with my code?

try
{
    return($x % $y); 
    throw new Exception("Divide error..");
}
catch(Exception $e){
    echo "Exception:".$e->getMessage();
}

I got this warning:

Warning: Division by zero in file.php

The catch block is not run. What am I doing wrong?

I've fixed your indentation, you might want to check the preview box underneath the question area next time: you can see how your code will come out, and fix it up a bit for easier reading. Remember, the easier you question is to read, the more answers you might get? — Nanne, May 18 '11 at 06:06
@ibu: thanks, i have removed the return statement. Now i am able to catch the exception but it is still showing me warning.. — insomiac, May 18 '11 at 06:10

deceze · Accepted Answer · 2011-05-18T06:34:49.700

7

A warning is not an exception. Warnings cannot be caught with exception handling techniques. Your own exception is never thrown since you always return before.

You can suppress warnings using the @ operator like @($x % $y), but what you should really do is make sure $y does not become 0.

I.e.:

if (!$y) {
    return 0; // or null, or do something else
} else {
    return $x % $y;
}

edited May 18 '11 at 06:34

answered May 18 '11 at 06:07

deceze

510,633
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i have removed the return statement. Now i am able to catch the exception but it is still showing me warning.. – insomiac May 18 '11 at 06:11
@Aby If you remove the `return` statement, you'll **always** throw and catch the exception. Exceptions are completely useless here. And regarding the warning, read my answer again. – deceze May 18 '11 at 06:12

score 3 · Answer 2 · answered May 18 '11 at 06:06

3

Yes, you are executing the return before the throw. Hence the throw is never executed and no exception is thrown nor caught.

answered May 18 '11 at 06:06

user703016

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Ok. I have removed the return statement now. But it is still showing me warning.. – insomiac May 18 '11 at 06:12

score -1 · Answer 3 · answered May 18 '11 at 06:10

this is how it should be done

$value;

try
{
    $value = $x%$y; 
}
catch(Exception $e){
  throw new Exception("Divide error..");
  echo "Exception:".$e->getMessage();
}

return $value

But since you are getting a warning if you want to hide the error and handle it discretely You can use the @ sign

$value = @$x%$y;

now you can test the value and see if it has the value it has

Divide by Zero warning is not caught in a PHP try/catch block

3 Answers3

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