PHP 4 and the integrated Zend engine have greatly improved PHP's
performance and capabilities, but great care has been taken to
break as little existing code as possible. So migrating your code
from PHP 3 to 4 should be much easier than migrating from
PHP/FI 2 to PHP 3. A lot of existing PHP 3 code should be
ready to run without changes, but you should still know about the
few differences and take care to test your code before switching
versions in production environments. The following should give you
some hints about what to look for.
User Contributed Notes Migrating from PHP 3 to PHP 4
11-Jul-2002 05:39
In PHP3, setting an array element to a variable did not cause the element
to be created. In PHP4, it does and it doesn't. For example, in both
versions, the following:
$x['y'] = $z;
if (!isset($x['y'])) echo "not "; echo "set";
where $z is not set, will output "not set", as expected.
*However*, in PHP4, walking through the array with each() will return the
'y' element. In PHP3 it doesn't.
11-Jul-2002 07:37
Sorry, that should read "...setting an array element to a variable
which is not set...."
Hopefully someone will clear up my silly typo at some point.
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