Subs and Functions

Subs do not return a value
Functions can return a value

Call

Transfers control to a Sub procedure, Function procedure, or dynamic-link library (DLL) procedure.

when using “Call”, the arguments must be in parenthesis; when not using “Call”, the arguments cannot be in parenthesis

' Call a Sub procedure.
Call PrintToDebugWindow("Hello World")    
' The above statement causes control to be passed to the following
' Sub procedure.
Sub PrintToDebugWindow(AnyString)
    Debug.Print AnyString    ' Print to the Immediate window.
End Sub
 
' Call an intrinsic function. The return value of the function is
' discarded.
Call Shell(AppName, 1)    ' AppName contains the path of the 
        ' executable file.
 
' Call a Microsoft Windows DLL procedure. The Declare statement must be 
' Private in a Class Module, but not in a standard Module.
Private Declare Sub MessageBeep Lib "User" (ByVal N As Integer)
Sub CallMyDll()
    Call MessageBeep(0)    ' Call Windows DLL procedure.
    MessageBeep 0    ' Call again without Call keyword.
End Sub