Roku Developer Program

[matrixebiz]

Hello, just wondering the difference between a Sub routine and a Function routine.

Are Sub routines always ran in the code automatically and a Function routine needs to be called upon within the code?

Or do you always have to call upon them both within the code script for them to run? Thx

[squirreltown]

"matrixebiz" wrote:
Or do you always have to call upon them both within the code script for them to run? Thx

Yes. The difference is that a function can return something.

[EnTerr]

sub is just a special case of function. 
Sub is a function that does not return a value (formally, its return type is "as void"). Also, from what i remember you cannot have an anonymous/lambda sub literal:

myFun = function(): ? "fun": end function   ' can haz '
mySub = sub(): ? "sub": end sub ' cannot haz '

Consider "sub" as a shortcut when writing procedures/subroutines.

[Komag]

Maybe I'm missing some usefulness, but I don't have a single sub, only Functions, with some "AS VOID" where needed. Is there a benefit to using sub?

[belltown]

"Komag" wrote:
Maybe I'm missing some usefulness, but I don't have a single sub, only Functions, with some "AS VOID" where needed. Is there a benefit to using sub?

No benefit that I can see. I very rarely use subs, except for main(), which I don't expect to ever return a value.

[EnTerr]

Indeed. Sub is syntax sugar like "don't" - you "do not" have to use the short form  🙂 

[renojim]

It's much quicker to type Sub/End Sub than Function ... as void/End Function.  😄

[marcelo_cabral]

As a retro-developer (there is such word ?) that worked with Visual Basic 1.0 up to VB.Net I also use Sub a lot, when there is no return value I just think there is no point to write a Function "as void"

🙂

[EnTerr]

Guys, you do know that in B/S declaring the return and arguments types is largely in the "good manners" category and does not speed up the code, right?
Just checking  🙂

[NND]

You can declare sub with return value and use it as a function. One real difference is the one mentioned by EnTerr, no anonymous subs.