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What's the deal with a leading underscore in PHP class methods?

I think it’s pretty descriptive… what does it mean if you see a function starting with an underline in php? I’ve seen it many times and I still don’t know what it is! It still works but it just looks weird starting with an underline and I suspect it’s just a convention but I don’t know what it is. I am not talking about double underlined functions ( i.e. __construct()) but a single underline.

My best guess is that it means it’s your own unique function and you want others to know that?

Answer 1

There’s no significance as far as the language itself is concerned, but a single-underscore prefix is usually used to indicate “private” or “hidden” class members.

Sometimes you see the underscore prefixed to all private and protected members, just to make it more obvious that they aren’t publicly available. Other times, regardless of the access level, an underscore can indicate an “internal” function, one that can technically be used, but the use of which is discouraged.