Macros in VB ???

How can I create my own macros, not using VBA, using normal Visual Studio VB 6?

Because the Win32, eg.

#If Win32 Then
#End if

this win32 is a standard macro, or as we like to call it in c/c++ a #define statement.

I need to know why I can't create my own macros, or if you can how can you, and also, why can't you use

// Determines what windows version currently running, ect.
#If LOBYTE(LOWORD(GetVersion())) = 5 Then
#End if

Now these # statements determines what gets compiled at runtime, leaving cleanness for Win16/Win32/Win64 code, but why come you can't use a fuction in an #If statements, to determine what the outcome would be.

Because these statements gets compiled prior to execution, the compiler should actually know the value of:
#If LOBYTE(LOWORD(GetVersion())) = 5 Then
#End if

beforehand. But a Macro is allowed which is almost like a function ????

And why can't you have multiple/nested #if statements:

#If ? Then
#If ? Then
#End if
#End if

????

Thanks in advance
xIRC