WinAPI: GetDiskFreeSpaceEx - 获取磁盘容量信息

//声明:
GetDiskFreeSpaceEx(
lpDirectoryName: PChar;                          {磁盘根路径}
var lpFreeBytesAvailableToCaller: TLargeInteger; {可用空间}
var lpTotalNumberOfBytes: TLargeInteger;         {总空间}
TotalFree: PLargeInteger                         {剩余空间}
): BOOL;

//举例:
procedure TForm1.FormCreate(Sender: TObject);
var
d1,d2,d3: Int64;
begin
GetDiskFreeSpaceEx('C:',d1,d2,@d3);

Memo1.Clear;
with Memo1.Lines do
begin
Add(Format('可用空间: %f GB',[d1/1024/1024/1024]));
Add(Format('总空间: %f GB',[d2/1024/1024/1024]));
Add(Format('剩余空间: %f GB',[d3/1024/1024/1024]));
end;
end;

//效果图: