Best Way to declare constants?

blintzbug

This is kind of a style question, I believe:

What is the best way (or the standard way? ) to declare constants? For example, I have a php script I am using where I periodically change the name of the upload directory, so I simply declared at the top of the script:

$upload_dir="/upload1";

The idea being I change it there, and then I don't have to go through the whole progam and change every hard-coded instance of the upload directory. Simple.

But then in order to use it in a function, I have to delare:
global $upload_dir;

so I can actually use it. Kind of a pain. I've looked into the "declare" statement, but that's not really what I'm looking for either...

Also, is there a site out there that discusses PHP coding style?

thanks!

tsinka

Hi,

you can use define, like

define("CONSTANTNAME","thevalue");

You can use that constant within functions without using global.

echo CONSTANTNAME
(without $).

Thomas

devinemke

Originally posted by blintzbug
I've looked into the "declare" statement, but that's not really what I'm looking for either...

why not? it sounds like exactly what you are looking for. in fact i don't know of any other way of defining contacts other than [man]define[/man].

drawmack

well, by definition a variable's value can change during the execution of a program while a constant's value cannot. Unless your upload directory changes dynamically from within the script then you should be using a constant. However you also should never use global but instead pass the value as a parameter. That way if you copy and paste it you don't have to worry about a nasty global hanging around.

blintzbug

Originally posted by devinemke
why not? it sounds like exactly what you are looking for. in fact i don't know of any other way of defining contacts other than [man]define[/man].

using declare, what previously was:

print ("<img src=\"$upload_path1$pic_file\">");

became:

print ("<img src=\"UPLOAD_PATH1$pic_file\">");

And, of course, that didn't work, as the constant needs to be evaluated in order for it to work. I could do:

$path = UPLOAD_PATH;
print ("<img src=\"$path1$pic_file\">");

And that would be fine. I just thought there might be a better way.

devinemke

Originally posted by blintzbug
just thought there might be a better way.

there is:

define('UPLOAD_PATH', '/path/to/upload/');
print('<img src="' . UPLOAD_PATH . $pic_file . '">');

blintzbug

awesome. Thanks for the help.