W1024组合有符号和无符号类型-扩展了两个操作数

问题描述

如何防止此警告？
[DCC警告] uFvSystem.pas（293）：W1024组合有符号和无符号类型-扩展了两个操作数

 函数LinkerTimestamp：TDateTime；超载; 
开始
结果：= PImageNtHeaders（HInstance + PImageDosHeader（HInstance）^ ._ lfanew）
 ^ .FileHeader.TimeDateStamp / SecsPerDay + UnixDateDelta; 
结尾； 
  

解决方案

错误消息表明您正在使用混合有符号和无符号操作数。唯一的整数算法在这里：

  HInstance + PImageDosHeader（HInstance）^ ._ lfanew 
  

第一个操作数是无符号的，第二个操作数是有符号的，即使它必须是正数也是如此。

您可以通过强制转换来取消警告。最好在无符号上下文中执行算术运算，从而避免范围检查错误。因此，强制类型转换放置在第二个操作数周围：

  HInstance + NativeUInt（PImageDosHeader（HInstance）^ ._ lfanew）
  

或

  HInstance + Cardinal（PImageDosHeader（HInstance）^ ._ lfanew）
  

如果您的Delphi较旧具有 NativeUInt 。

但是，您实际上是在对指针执行算术运算，所以我会这样写：

  PByte（HInstance）+ PImageDosHeader（HInstance）^ ._ lfanew 
  

或

  PAnsiChar（HInstance）+ PImageDosHeader（HInstance）^ ._ lfanew 
   
 
 
  PByte 不支持算术运算。 
 
How can I prevent this warning?
[DCC Warning] uFvSystem.pas(293): W1024 Combining signed and unsigned types - widened both operands
function LinkerTimestamp: TDateTime; overload;
begin
  Result := PImageNtHeaders(HInstance + PImageDosHeader(HInstance)^._lfanew)
   ^.FileHeader.TimeDateStamp / SecsPerDay + UnixDateDelta;
end;
 解决方案 
The error message indicates that you are performing integer arithmetic with mixed signed and unsigned operands. The only integer arithmetic is here:
HInstance + PImageDosHeader(HInstance)^._lfanew
The first operand is unsigned, the second is signed, even though it must be positive. 
You can suppress the warning with a cast. It is better to perform the arithmetic in an unsigned context and so avoid range check errors. Hence the cast is placed around the second operand:
HInstance + NativeUInt(PImageDosHeader(HInstance)^._lfanew)
or
HInstance + Cardinal(PImageDosHeader(HInstance)^._lfanew)
if you have an older Delphi that does not have NativeUInt. 
However, you are actually performing arithmetic on pointers and so I would write it like this:
PByte(HInstance) + PImageDosHeader(HInstance)^._lfanew
or
PAnsiChar(HInstance) + PImageDosHeader(HInstance)^._lfanew
in older Delphi versions for which PByte does not support arithmetic. 
                        
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