Question

I am looking at VB6 code and I see a statement as follows –

       Public Sub CheckXYZ(abc As Integer)

       If abc <> pqr Then SetVars abc

And when I click on go to definition on SetVars, I am taken to the following definition-

      Private Sub SetVars(i As Integer)

I am new to VB. Is this something that is common in VB, to allow function calls without the paranthesis?

Answer 1

As Ryan has pointed out, parentheses should only be used when calling a function that will return a value.

One pitfall I would like to add is that if you actually DO use parenteses unintentionally when calling a Sub, VB6 will pass the parameter by value instead of by reference.

When the Sub takes more than one parameter, this is not a risk, since this is an illegal syntax in VB6:

SomeFunc (arg1, arg2)

But consider this example:

Sub AddOne(ByRef i As Integer)
  i = i + 1
End Sub

Sub Command1_Click()
  Dim i as Integer

  i = 1
  AddOne i    'i will be passed by reference and increased by 1
  Msgbox i    'Will print "2"
  AddOne (i)  'i will be passed by value, so the return value will be lost!!
  MsgBox i    'Will still print "2"!!
End Sub

So be aware of how you use the parentheses, a small change may have unexpected effect.