一些函数

char t[30];
strcpy (t, "接收上线请求");
 
char sql[300] = {0};
sprintf (sql, "update tab_zxk set wssj = %d where kh = \'%s\'", nowtime, buf->card_no);
memset(sql, 0, 300);

钩子函数:
g_Hook = SetWindowsHookEx(WH_CBT, CBTProc, NULL, GetCurrentThreadId()); 
LRESULT CALLBACK CBTProc(
  int nCode,      // hook code
  WPARAM wParam,  // depends on hook code
  LPARAM lParam   // depends on hook code
)
{
// if(g_hWnd == wParam )
 if(nCode == HCBT_MINMAX && lParam == SW_MINIMIZE)
  return 1;
 else
  return CallNextHookEx(g_Hook, nCode, wParam, lParam);
}

文件操作:

 int newkalen=strlen(kahao);
 char *pKa=new char[newkalen];
 strncpy(pKa,kahao,newkalen);
 pKa[newkalen] = '\n';
 FILE *fp  = NULL;
       if((fp=fopen(m_KahaoFile,"a+"))==NULL)  //打开卡号包明文
 {
  return 0;
 }
 fwrite (pKa, newkalen+1, 1, fp);   \\其中添加一个'\r'
       fclose(fp);
       delete []pKa;
//////////////////////
                        char m_KahaoBuf[KAHAOBUFNUM][MAXKALEN];
                        char c;
                       for(i=0;i<readcount;i++)  
   {
    k=0;
    while((c=fgetc(fp))!=EOF)    //读出卡号到缓冲区
    {
                       #ifdef WIN32
                       #else
     if('\r'==c)continue;
                       #endif
     if('\n'==c)
     {
      m_KahaoBuf[i][k]='\0';
      break;
     }
     m_KahaoBuf[i][k]=c;
     k++;
    }
   }

//////////////////////////////

                                         //写入临时文件
                                         FILE *fptemp = NULL;

                          fptemp=fopen(KahaoFileTemp,"w"); 
     for(i=0;i<=readcount;i++)
     {
      k=0;
      while('\0'!=m_KahaoBuf[i][k])  //注意'\0'
      {
       fputc(m_KahaoBuf[i][k],fptemp);
       k++;
      }
      fputc('\n',fptemp);    //注意'\n'
     }
                                         fclose(fptemp);

///////////////////////////
  socket程序:
        const char *pHost;
        int nPort;
        struct sockaddr_in addr;        //sockaddr_in包括in_addr结构
 struct hostent *phe = NULL;

 memset (&addr, 0, sizeof (addr));
 addr.sin_family = AF_INET;
 addr.sin_port = htons (nPort);

 if ((addr.sin_addr.s_addr = inet_addr (pHost)) == (unsigned long int) -1)        
 {
  if ((phe = gethostbyname (pHost)) == NULL)
   return 0;

  memcpy ((char *)&addr.sin_addr, phe->h_addr, phe->h_length);
 }

 connect (m_nSock, (struct sockaddr *)&addr, sizeof (addr)) ;
//////////////////////////////////////////

       struct in_addr in_address;                 //sockaddr_in包括in_addr结构
        char a[20];
 in_address.s_addr = n;
 strcpy (a, inet_ntoa (in_address));           


自定义消息:
头文件:
#define WM_RECVDATA  WM_USER+1
 afx_msg void OnRecvData(WPARAM wParam,LPARAM lParam);

cpp文件:
ON_MESSAGE(WM_RECVDATA,OnRecvData)