一次疏忽导致的bug

Posted 2020-07-30 好好学习 天天向上

NBB_PUT_SHORT 这个宏是按char* 类型算指针的
实际工作中，没有注意这一点，输入指针类型 强转为了 SHORT* 
导致 填充的内容错误

这是第一次在工作中遇到 指针类型相关的问题
值得记录一笔

 1 // ConsoleApplication1.cpp : 定义控制台应用程序的入口点。
 2 //
 3 
 4 #include "stdafx.h"
 5 #include <stdio.h>
 6 #include <string.h>
 7 #include <stdlib.h>
 8 
 9 typedef unsigned char    NBB_BYTE;     /* 8 bits                             */
10 typedef  signed  char    NBB_CHAR;     /*                                    */
11 typedef  signed  short   NBB_SHORT;    /* 2 byte signed integer              */
12 typedef unsigned short   NBB_USHORT;   /* 2 byte unsigned integer            */
13 typedef  signed  long    NBB_LONG;     /* 4 byte signed integer              */
14 typedef unsigned long    NBB_ULONG;    /* 4 byte unsigned integer            */
15 typedef  signed  int     NBB_INT;      /* >= 2 byte signed integer (machine  */
16                                        /* word)                              */
17 typedef unsigned int     NBB_UINT;     /* >= 2 byte unsigned integer         */
18                                        /* machine word)                      */
19 typedef          int     NBB_BOOL;     /* boolean                            */
20 typedef          void    NBB_VOID;     /* void if supported, char otherwise  */
21 
22 typedef NBB_BYTE*   BFD_PUC_ALARM_INFO;
23 
24 BFD_PUC_ALARM_INFO g_pucAlarmInfo;         /* ״̬Éϱ¨Ð­ÒéÕ» */
25 
26 #define NBB_PUT_SHORT(B, S)                            27              (B)[0] = (unsigned char)((S) >> 8);            28              (B)[1] = (unsigned char)((S) & 0xFF)
29 
30 void init()
31 {
32     g_pucAlarmInfo = (BFD_PUC_ALARM_INFO) malloc(1000);
33     memset(g_pucAlarmInfo, 0, 1000);
34 }
35 int main()
36 {
37     NBB_BYTE ucLocalSlot = 0;
38     NBB_BYTE ucMainSlot = 0;/* Ö÷ÓÃÖ÷¿ØÅ̵IJÛλºÅ */
39     NBB_BYTE *pucInfoTmp = NULL;
40     NBB_USHORT *pusData = NULL;
41     NBB_ULONG ulDataLenth = 0;
42 
43     init();
44 
45     pucInfoTmp = g_pucAlarmInfo + 24;
46     pusData = (char *)pucInfoTmp;
47     *pusData = 0x0001;
48 #if 0
49     NBB_PUT_SHORT(pusData, 0x0001); /* ÌîдÀàÐÍ */
50 #else
51     pusData[0] =(unsigned char)( 0x0001 >> 8);
52     pusData[1] =(unsigned char)( 0x0001 & 0xff);
53 
54 #endif
55     pucInfoTmp = pucInfoTmp + 2;
56     return 0;
57 }