Avoiding multiple includes

Anon

This regards the practice of protecting included files so you can't include them multiple times and get "already defined" errors.
One solution I saw which I really liked was this:
<pre>
// beginning of included file
if (defined("CONSTANT"))
return;

define("CONSTANT");
//... rest of content
</pre>
The only problem is that PHP (latest v3) starts acting strange when I get really tangled deep multi-includes. By strange I meant skipping included files (that aren't "protected") in a random fashion; I haven't been able to make rhyme or reason out of the behaviour. And it only occurs in really tangled include situations (making it hard to debug).
It doesn't choke on this, though:
<pre>
// beginning of included file
if (!defined("CONSTANT")) {
define("CONSTANT");
//... rest of content
}
</pre>
Now, I don't like this because it requires blocking off the whole file.
My question is, why in the world would one method work and the other not? Is this some mysterious bug?

Anon

I would suggest you use the method PEAR does..an array of booleans that flag whether a file has been included and if you are including instead of requiring, you can do:
if (!$array["thispage"]) return false;

at the top of your script.

Anon

I'm not sure why one would use an array instead of a single variable, or better yet, a constant. Naming collisions can be avoided by using conventions, and there's the possibility that your $array may be unexpectedly out of the current scope.

Anyways, I haven't been able to try this, but I would expect that since it uses the return method it would have the same results.

It occurred to me that because the include structure is incredibly convoluted I may just be missing an extra { somewhere, and that's causing the strange errors. However, the problem went away when I switched a few files to the blocked method. Even if it is human error, the blocked method vs return method is more fault tolerant.

Anon

Have you looked at the new function for php4.0 include_once()??

Anon

PHP4.0.3 has a bug that effects include files

We reported it a few days back and it has now been fixed in PHP4.0.3pl1

I would upgrade ASAP

Regards
Darren
http://www.php4hosting.com