Im now completely rewriting a CMS and really want it to be good (done everyone?) and am trying to get it as flexible as possible.

anyway i noticed that on alot of big scripts they seem to use DEFINE for alot of things :/ whats the benifits of using this over than jsut haveing a $var with the info or something?

Just 2
1) Once a constant have been defined, it cannot be changed.
2) If you define a constant in a php page directly, it will be available even in a class/function where a $variable would need to be explicitly passed to the function.
Constants are not limited by a scope.

Appart from that, there are no differences in the two.

Just for number 2 that you mentioned, I think that it would be worth it.

so would it be advised if i have site wide settings or soemthing like that to use it?

how are they used

There are other ways to gain superglobal-like scope then through constants (lookup the "singleton" pattern for example). You should only use constants for values that should never change.

Application-wide values are best kept in constants: Initiation variables (database names, paths, modes like debug mode), error codes, option names and things like that. Actual settings for the app like "Show number of users on index?" and such should be in variables. If it will ever change in the use of the app, then it should probably be in a variable.

Well, you can see how define works in my signature :P

http://www.php.net/define

yea i have seen how to define i just mean to actually like use the thing after it has been defined?

like for instance if i wanted to use

define('prog_version','1.0');

how would i then show prog_version?

The link that coolkbk585 gave you (not his signature) shows in the example EXACTLY how you would show prog_version. And it's not like it's a difficult link to come by!

Geez Dan, and here I was thinking that you had started to research things by yourself...

PHP Code:

define('prog_version','1.0');

echo "your program version is ".prog_version;  // ::> right
echo "your program version is prog_version";   // ::> false, prog_version will not be interpreted 


Simply, you cannot use an define into a string.

tripy: I don't get your post. Are you saying that that is a benefit or are you just making a statement about the fact that it doesn't get interpreted?

I'm making a fact.

I was just explaining to Dan, that he cannot use a defined value in a string like we do with a variable.

I think define is worth while for security when RAW is concerned.

Ok sorry i missed the link there thanks,

What do you mena by RAW?

You can use define when you have alot of php files included in each other and want to define a variable that will never change.

I personally use it alot for paths. For sample you don't want to rewrite the path of your image folder evry time you use it.

define('IMAGE_PATH','site/files/lost/somewhere/ontheserver/images/');

echo "<img src='IMAGE_PATH$image'>";

you can notice that you don't need to use $ or any " because IMAGE_PATH will be replaced by 'site/files/lost/somewhere/ontheserver/images/' before the script is compiled. Its like if you would use "replace" in a text file or str_replace on a string.

i also personally use it for option, for sample if you want to put your website on debug mode.

define('MODE','1'); // 0 = normal, 1 = debug

Thanks all, i was mainly curious as it seemed very few and yet alot of scritp use it, (that makes sense to me )
Dan