struct sizeof结果不期望 [英] struct sizeof result not expected

问题描述

我有一个如此定义的结构：

  typedef struct _CONFIGURATION_DATA {
 BYTE configurationIndicator; 
 ULONG32 baudRate; 
 BYTE stopBits; 
 BYTE parity; 
 BYTE wordLength; 
 BYTE flowControl; 
 BYTE padding; 
} CONFIGURATION_DATA; 
  

现在，根据我的推算，该结构体是10个字节长。然而，sizeof报告，它是16个字节长？任何人都知道为什么？

我正在使用Windows DDK中的构建工具进行编译。

解决方案

比对。

使用

#pragma pack ）

... struct到这里...

#pragma pack（）

我还建议重新排序，并且如果必要的话用RESERVED字节填充，这样多字节整数类型将更好地对齐。这将使CPU的处理速度更快，您的代码更小。

I have a a struct defined thusly:

typedef struct _CONFIGURATION_DATA {
    BYTE configurationIndicator;
    ULONG32 baudRate;
    BYTE stopBits;
    BYTE parity;
    BYTE wordLength;
    BYTE flowControl;
    BYTE padding;
} CONFIGURATION_DATA;

Now, by my reckoning, that struct is 10 bytes long. However, sizeof reports that it is 16 bytes long? Anyone know why?

I am compiling using the build tools in the Windows DDK.

解决方案

Alignment.

use

#pragma pack(1)

...struct goes here...

#pragma pack()

I would also recommend reordering things, and if necessary padding then with RESERVED bytes, so that multi-byte integral types will be better aligned. This will make processing faster for tbe CPU, and your code smaller.

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