Programming Reference Manual
 
Syntax
 
FreeFile[]
 
Description
Return the next unused shared stream number (greater than or equal to 256). Streams 1 through 255 are private to each macro. Streams 256 through 511 are shared by all macros. 
See Also
 
Example
 
Sub Main
    Debug.Print FreeFile ' 256
    FN = FreeFile
    Open "XXX" For Output As #FN
    Debug.Print FreeFile ' 257
    Close #FN
    Debug.Print FreeFile ' 256
End Sub