Interesting Return behavior

[Shaggy Hiker]

I haven't seen anybody comment on this yet, and I haven't been able to come up with some use for it, but it does seem like there ought to be something clever that you could do with it:

Consider these two short functions:

private function func1(ByRef n as integer) as integer
 n=5
 return n
 
 n=6
 
end function
 
private function func2(ByRef n as integer) as integer
 try 
  n=5
  return n
 catch ex as exception
  'Do nothing here.
 Finally
   n=6
 end try
end function

Now consider using the two in this fashion:

public sub Main()
  dim v as integer
  dim n as integer
 
  n=0
  v=func1(n)
  
   'What does n equal? What does v equal?
 
   n=0
   v=func2(n)
 
end function

It may appear that after calling func1 or func2, the variables v and n would be set to the same thing. Afterall, the only difference between the two functions is that func2 has error handling, which will never be called because no errors will arise in that code.

However, the results will not be the same. After calling func1, both n and v will be set to 5. After calling func2, v is 5, but n is 6!

In func1, the function returns at the return statement, and the n=6 line is never executed. In func2, the return simply sets the return to 5, but then the finally block executes, and n is set to 6. Since n is passed by reference, it is changed.

I can't think of an obvious use for this, but it seems there is a window there to use a Finally block to do some odd things.

Any ideas?

[crptcblade]

Yes, the Finally block is executed regardless of whether there is an error or a return statement. It would be where you would put your Close for a file or database connection, so you'd only need to have it in the one place.

[Shaggy Hiker]

True, there are standard things that can be done there, but it seems like there ought to be some other use for a chunk of code that executes after the return statement. It's sort of like an OnClosing event in a window, but I have never actually used one of them for anything, either.

On the other hand, I realize now that I have done some stupid things because I didn't realize this behavior.