2007. 03. 21, szerda keltezéssel 00.04-kor Richard Lynch ezt írta: > On Tue, March 20, 2007 11:08 am, Ford, Mike wrote: > >> what do you want with that '@' here? > >> that operator can be used to suppress error messages when calling > >> functions but not when using a variable > > This is most definitely way wrong. > > > What complete tosh! @ is a unary operator, so can be applied to any > > expression. > > > > Proof: > > > > <?php > > echo "no @ --", $HTTP_GET_VARS['bogus'], "<br />\n"; > > echo "with @ --", @$HTTP_GET_VARS['bogus'], "<br />\n"; > > ?> > > > > Result: > > > > no @ -- > > Warning: Undefined index: bogus in > > c:\www-lco\scripts_etc\lco\php\test.php on line 18 > > > > with @ -- > > > > > > Also: > > > > <?php > > $a = 123; > > echo "no @ --", $a/0, "<br />\n"; > > echo "with @ --", @($a/0), "<br />\n"; > > ?> > > > > Result: > > > > no @ -- > > Warning: Division by zero in c:\www-lco\scripts_etc\lco\php\test.php > > on line 19 > > > > with @ -- > > > > > > Not that I'm necessarily advocating this as a technique, but let's not > > spread disinformation! > > While it has now been proven that @ is "more" than a function > error-suppressant, I suspect it may technically be a Language > Construct rather than a simple unary operator... > > Not that I can come up with anything yet to prove it, as all my > examples so far were total syntax errors... > > Although I did find an interesting anomoly... > > What would you expect this to output? > <?php @ ?> > > Hint: > I figured it would apply the @ to no expression at all and do nothing. > I was wrong. > > I suppose I could try to read PHP source and figure all this out > someday... actually I tried it and the output suprised me also it was Parse error: syntax error, unexpected ';' in /var/www/tests/kukactest1.php on line 1 although I tried it with the unary operator ! <?php ! ?> that produces the same output so this behaviour is probably the way operators behave... but it is really interesting ;) greets Zoltán Németh > -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
