PHP header（）函数

Question

I am trying to integrate a website from a partner of my company, and I running into this line here:

header("Location: field/index.php", overwrite); 

I browsed the PHP manual of header() function, but can't find a parameter called overwrite. Can someone give me any clue?

Answer 1

It (overwrite) could be a constant, for example

define('overwrite', true);
header("Location: field/index.php", overwrite);

In this case overwrite represents Boolean true and which is being used to replace a previous header.

Though, constants should be declared using uppercase letters but it doesn't throw any errors if someone uses lowercase letters instead. Recommended way to define a constant is

defined('OVERWRITE') or define('OVERWRITE', TRUE);

It's worth mentioning that, any constant defined this way is available globally, throughout the script/application and basically developers define constants at the very beginning of script or an application and it could be defined in a different file (which is included/executed on start up) so, you may don't see it in the current script.