How efficient is define in PHP?

Question

C++ preprocessor #define is totally different.

Is the PHP define() any different than just creating a var?

define(\"SETTING         


        

Answer 1

Here are the differences, from the manual

• Constants do not have a dollar sign ($) before them;
• Constants may only be defined using the define() function, not by simple assignment;
• Constants may be defined and accessed anywhere without regard to variable scoping rules;
• Constants may not be redefined or undefined once they have been set; and
• Constants may only evaluate to scalar values.

For me, the main benefit is the global scope. I certainly don't worry about their efficiency - use them whenever you need a global scalar value which should not be alterable.