[Function declarations]
FUNCTION ulong GetLogicalDrives() LIBRARY "Kernel32.dll"
FUNCTION uint GetDriveType( Ref String as_root_path ) 
   LIBRARY "kernel32.dll" ALIAS FOR "GetDriveTypeA"

[PB function String of_GetCDRootPath()]

integer   li_ctr

string    ls_root
ulong     lul_drives, lul_rem

lul_drives = GetLogicalDrives()

DO
  lul_rem = MOD(lul_drives,  2 )
  IF lul_rem =  1  THEN
     ls_root = Char(li_ctr +  64 ) + ":\"
     IF GetDriveType(ls_root_path) =  5  THEN
        Return ls_root_path
     END IF
     li_ctr ++
  END IF
  lul_drives /=  2 
LOOP UNTIL lul_drives =  0 

RETURN ""