isset vs empty vs is_null

Question

I\'m trying to write a script that when a user uploads a file and does not enter a name an error is returned. I\'ve tried using is_null, empty, and isset and they all do not

Answer 1

Ref this: different between isset, is_null, empty in PHP

• isset() mean $var is defined and not null
• is_null() mean $var is defined and null. throw an error if it is undefined.
• empty() is anything mean NO => false, 0, 0.0, "", "0", null, array()