用vs2010 c++编写收银机开钱箱

1.环境 Windows7 vs2010
2.语言 c++
3.设备 钱箱与打印机的LPT1口相连
4.控制指令  27 112 7（十进制）
5.代码

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1. CString sPort;
   
2.     //sPort.Format(_T("\\\\.\\LPT1"));//两种方法都行
   
3.     sPort.Format(_T("LPT1"));
   
4. #if 1
   
5.     //设置为重叠 异步IO
   
6.     HANDLE hPort = CreateFile(sPort,GENERIC_READ | GENERIC_WRITE,0,NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);//创建文件
   
7.     if (hPort == INVALID_HANDLE_VALUE || hPort == (HANDLE)ERROR_INVALID_HANDLE)
   
8.     {
   
9.         CString lsreturn = L"open fail";
   
10.         ExecutePrint(rect,LogFont,pDC,lsreturn.GetBuffer(0),lsreturn.GetLength(),DT_CENTER | DT_BOTTOM | DT_SINGLELINE);
    
11.         return false;
    
12.     }
    
13.     char lco[4];
    
14.     
    
15.     lco[0] = 27;
    
16.     lco[1] = 112;
    
17.     lco[2] = 7;
    
18.     lco[3] = '\0';
    
19. 
    
20.     DWORD writebyte = 0;
    
21.     DWORD writecount = 4;
    
22. 
    
23.     OVERLAPPED* pOverlapped = new OVERLAPPED;
    
24.     ZeroMemory(pOverlapped, sizeof(OVERLAPPED));
    
25.     pOverlapped->Offset = 0;
    
26.     pOverlapped->OffsetHigh = 0;
    
27.     pOverlapped->hEvent = 0;
    
28.     //pOverlapped->hEvent = (HANDLE) this;
    
29.     int lret = 0;
    
30.     lret = WriteFile(hPort,lco,writecount,&writebyte,pOverlapped);//向文件中直接写命令
    
31.     if (lret == 0)
    
32.     {
    
33.         int err = GetLastError();
    
34.         if (GetLastError() == ERROR_IO_PENDING)//重叠IO进行中
    
35.         {
    
36.             GetOverlappedResult(hPort,pOverlapped,&writebyte,true);
    
37.         }
    
38.         else//其他的错误
    
39.         {
    
40.             delete pOverlapped;
    
41.             CloseHandle(hPort);
    
42.             CString lsreturn = L"Failed to write";
    
43.             ExecutePrint(rect,LogFont,pDC,lsreturn.GetBuffer(0),lsreturn.GetLength(),DT_CENTER | DT_BOTTOM | DT_SINGLELINE);
    
44.             return false;
    
45.         }
    
46.     }
    
47. #endif
    
48. 
    
49. #if 0
    
50.     //同步IO 2种方法都可以
    
51.     HANDLE hPort = CreateFile(sPort,GENERIC_READ | GENERIC_WRITE,0,NULL, OPEN_EXISTING, 0, NULL);
    
52.     if (hPort == INVALID_HANDLE_VALUE || hPort == (HANDLE)ERROR_INVALID_HANDLE)
    
53.     {
    
54.         CString lsreturn = L"open fail";
    
55.         ExecutePrint(rect,LogFont,pDC,lsreturn.GetBuffer(0),lsreturn.GetLength(),DT_CENTER | DT_BOTTOM | DT_SINGLELINE);
    
56.         return false;
    
57.     }
    
58.     char lco[4];
    
59.     lco[0] = 27;
    
60.     lco[1] = 112;
    
61.     lco[2] = 7;
    
62.     lco[3] = '\0';
    
63. 
    
64.     DWORD writebyte = 0;
    
65.     DWORD writecount = 4;
    
66.     int lret = 0;
    
67.     lret = WriteFile(hPort,lco,writecount,&writebyte,NULL);
    
68.     if (lret == 0)
    
69.     {
    
70.         int err = GetLastError();
    
71.         CloseHandle(hPort);
    
72.         CString lsreturn = L"Failed to write";
    
73.         ExecutePrint(rect,LogFont,pDC,lsreturn.GetBuffer(0),lsreturn.GetLength(),DT_CENTER | DT_BOTTOM | DT_SINGLELINE);
    
74.         return false;
    
75.     }
    
76. #endif
    
77.     CloseHandle(hPort);

打开LPT1文件
向文件中写入命令
关闭文件

另外，在网上还查到一些别的指令，如 27 112 0 60 225（十进制的）。但是中间的那个0会被看成空字符，指令会被截断，不知道用什么方法解决。