> -----Original Message-----
> From: Chris Hewitt [mailto:[EMAIL PROTECTED]
> Sent: 03 April 2003 09:26
> To: Justin French
[snip]
>
> What I have done is to do the addslashes/stripslashes assuming
> magic_quotes_runtime is off then force it off within my code
> beforehand
> with:
>
> if (ini_get('magic_quotes_runtime') == 1)
> {
> if (ini_set('magic_quotes_runtime','Off') == false)
> {
> echo "ERROR: Could not turn off
> magic_quotes_runtime\n";
> }
> }
>
> I found that ini_set would through an error if the seting was already
> made, hence the initial check. So far this seems OK, but it was only
> yesterday...
Something bugged me about this code and comment when I very first read it,
but it's taken an overnight cogitate to work out what it was. Dare I
venture that your previous code, which sometimes appeared to throw an error,
was simply:
if (ini_set('magic_quotes_runtime','Off') == false)
{
echo "ERROR: Could not turn off magic_quotes_runtime\n";
}
?
If so, there's a fundamental flaw here: as ini_set is defined to return the
previous value of the setting, or FALSE if it fails, a simple equality
comparison (==) to FALSE will succeed whenever the ini_set fails *or when
the previous value was 0 (off)*. To echo your error only when ini_set()
genuinely returns FALSE, you must do an identity comparison (===).
<rant-ish>
It can *never* be good practice to make an equality (==) or non-equality
(!=) comparison with TRUE or FALSE. Not only is this bad style, but it is
also inefficient. Consider:
if ($x==TRUE)
(where $x can be any arbitrary expression). PHP must first retrieve the
value of $x, convert it to Boolean (giving TRUE or FALSE) and then compare
it to TRUE -- yielding TRUE if $x was, er, TRUE and FALSE if $x was, duh,
FALSE. That's a whole extra unnecessary comparison, plus some obfuscation
for humans reading the code. So just use:
if ($x)
Taking the converse:
if ($x==FALSE)
this isn't quite so clear-cut. PHP will retrieve the Boolean value of $x
(TRUE or FALSE), then compare it to FALSE, yielding TRUE if $x was FALSE,
FALSE if it was TRUE. It's not immediately clear, but this comparison will
usually be more expensive than just doing a Boolean not (!) on the
expression. Stylistically, it's usually also clearer to read as
if (!$x)
-- IMO, it's better to have the clue that you're looking for the inverse
value at the front, and read it as "if not $x". (Well, I suppose you could
also write "if (FALSE==$x)", but personally I think that's just as bad as
the other way round!)
Finally, if you never have an == or != comparison to TRUE or FALSE, the rare
occasion when you actually need to do an === or !== test will be very
obvious and will alert someone reading the code (yes, even yourself several
months later!) that something special is going on.
</rant-ish>
Cheers!
Mike
---------------------------------------------------------------------
Mike Ford, Electronic Information Services Adviser,
Learning Support Services, Learning & Information Services,
JG125, James Graham Building, Leeds Metropolitan University,
Beckett Park, LEEDS, LS6 3QS, United Kingdom
Email: [EMAIL PROTECTED]
Tel: +44 113 283 2600 extn 4730 Fax: +44 113 283 3211
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