How PHP macro define is interpreted? -


for c/c++, think preprocessor macro processing before compiler compiles program , that's why macro name has literal or absolute, no variable allowed declared macro name.

in case of php, can declare this: define($name, $value); means, interpreter first interprets variable , macro defined, i.e. runtime macro processing.

which creates doubt that, macro processing ? if not what's purpose of introducing such keyword 'define'; have values cannot changed ?

or if there's macro processing, can explain, how working ?

for sake of completeness, there is constant defined @ compile-time :

const my_constant = 'something';

as opposed defining constants using define(), constants defined using const keyword must declared @ top-level scope because defined @ compile-time. means cannot declared inside functions, loops or if statements.

from php manual.

this current php version, 5.3.


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