在调用DiskFree, DiskSize 这两个函数的时候不用声明的吗？
RT

[解决办法]
SysUtils 中已经定义了:
function DiskFree(Drive: Byte): Int64;
var
TotalSpace: Int64;
begin
if not InternalGetDiskSpace(Drive, TotalSpace, Result) then
Result := -1;
end;

function DiskSize(Drive: Byte): Int64;
var
FreeSpace: Int64;
begin
if not InternalGetDiskSpace(Drive, Result, FreeSpace) then
Result := -1;
end;