I'm try to understand the difference between the use of the "^" character and the "~" character when setting the error_reporting values. For example I have the following in my php script:
if (version_compare(PHP_VERSION, '5.3.0') >= 0) {
error_reporting(E_ALL & ~ E_DEPRECATED & ~ E_USER_DEPRECATED & ~ E_NOTICE);
} else {
error_reporting(E_ALL ^ E_NOTICE);
}
I've read the manual page at:
http://php.net/manual/en/function.error-reporting.php
but I'm now more confused than ever. Is:
error_reporting(E_ALL & ~ E_DEPRECATED & ~ E_USER_DEPRECATED & ~ E_NOTICE);
the same as:
error_reporting(E_ALL ^ E_DEPRECATED ^ E_USER_DEPRECATED ^ E_NOTICE);
those are bitwise operators: http://php.net/manual/en/language.operators.bitwise.php
error_reporting(E_ALL & ~ E_DEPRECATED & ~ E_USER_DEPRECATED & ~ E_NOTICE);
would mean E_ALL and NOT E_DEPRECATED and NOT E_USER_DEPRECATED & NOT E_NOTICE
while
error_reporting(E_ALL ^ E_DEPRECATED ^ E_USER_DEPRECATED ^ E_NOTICE);
would mean E_ALL except E_DEP.... etc.
I think the more relevant answer to your question was listed in a comment on the error reporting page on php.net which I'll repost here:
The example of E_ALL ^ E_NOTICE is a 'bit' confusing for those of us not wholly conversant with bitwise operators.
If you wish to remove notices from the current level, whatever that unknown level might be, use & ~ instead:
<?php //.... $errorlevel=error_reporting(); error_reporting($errorlevel & ~E_NOTICE); //...code that generates notices error_reporting($errorlevel); //... ?>^ is the xor (bit flipping) operator and would actually turn notices on if they were previously off (in the error level on its left). It works in the example because E_ALL is guaranteed to have the bit for E_NOTICE set, so when ^ flips that bit, it is in fact turned off. & ~ (and not) will always turn off the bits specified by the right-hand parameter, whether or not they were on or off.