Re: Does passing an uninitialized array variable initialize it? (PHP 5)

google2006@xxxxxxxxxxxxxxxx wrote:
The following code never sees the end of the array, and generates an
out of memory error under PHP5 (both CLI and Apache module) :

while (isset($rank[$i])) {
$rank[$i] = trim($rank[$i++]);
}

Moving the post increment to a separate line fixes this issue:

while (isset($rank[$i])) {
$rank[$i] = trim($rank[$i]);
$i++;
}

For some reason PHP5 appears to be initializing $rank[($i+1)] each
time, perhaps because it's passing the value to trim(). The subsequent
isset() test on that element succeeds so the loop continues
indefinitely as each new element is initialized.

It works as expected under PHP4, stopping once it hits the end of the
array. I can't find any documentation which hints at any change to the
handling of uninitialized variables which caused this code to break.

Thanks in advance for any help...

Regardless of anything else, in the expression trim($rank[$i++]), you are
referencing an uninitialised variable and that is bad programming practice
and should throw an error if error checking is set high enough.


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