参见英文答案 >
E2099 Overflow in conversion or arithmetic operation1个
const minDriveFreeSpace: Int64 = 1024*1024*1024*99;
和
var minDriveFreeSpace: Int64; begin minDriveFreeSpace := 1024*1024*1024*99;
会发出：
[dcc32 Error] DataStoreLocator.pas(92): E2099 Overflow in conversion or arithmetic operation
这是Delphi最大的错误还是限制.常数整数值？
解决方法
您需要在右侧将至少一个值强制转换为Int64.例如,这两个在XE6上编译得非常好：
const minDriveFreeSpace = Int64(1024) * 1024 * 1024 * 99; var minDriveFreeSpace2: Int64; begin minDriveFreeSpace2 := Int64(1024)*1024*1024*99;
请注意,它可以是任何一个施放的右值.例如,这也同样有效：
const minDriveFreeSpace = 1024 * 1024 * 1024 * Int64(99);
这在Delphi language guide中有记录(虽然相当差) – 强调我的：
In general,arithmetic operations on integers return a value of type Integer,which is equivalent to the 32-bit LongInt. Operations return a value of type Int64 only when performed on one or more Int64 operands. Therefore,the following code produces incorrect results:
var I: Integer; J: Int64; ... I := High(Integer); J := I + 1;
To get an Int64 return value in this situation,cast I as Int64:
... J := Int64(I) + 1;