Tip: forget about C++ in the context of PHP, learn PHP, and become a PHP programmer.

PHP isn't really based on C++, it's based on C - but via Perl, which in turn was based on shell scripts - hence $ in front of variable names.

If you're writing OO, bear in mind that scoping doesn't work like in C++, i.e.

$this->x
and
$x

Are completely different, $x will always be treated as a local (unless you've done global $x).

Read up about variable scoping, because it confused me when I started PHP.

Basically, PHP has function scope by default - anything which isn't taken from somewhere else or qualified, is a local variable.

PHP does *NOT* have lexical scope, like C++. A closed curly brace does not cause locals to go out of scope unless it's the end of a function. So

function Something($blah) { if ($blah) {   $x = 42;} else {  $x = 99;}// $x still in scope}

Mark

Tips for anyone programming PHP:

- Use the latest version of PHP *if possible*. Don't worry about backwards compatibility. PHP is NOT backwards compatible generally.
- DO enable all errors and warnings with error_reporting
- DO write an error handler which shouts, screams, kicks and throws a massive fit as soon as it sees even an E_NOTICE
- DO log errors etc

The problem is, a lot of mistakes cause E_NOTICEs. If you disable them (as they are by default), they are completely silent, so you won't see them at all and can get away with blue murder.

The other problem is, a lot of stuff generates an E_WARNING if it has failed completely - e.g. opening a file, connecting to a database. In practice, there is rarely any need to continue running code using the "Keep running headlong into oblivion" school of error non-handling.

So I really recommend you write an error handler which terminates the script as soon as it sees a (non-suppressed) E_WARNING. Another option is to throw an exception which the caller can catch if they *really* want to continue.

Mark