驱动程序和应用程序之间通信（ForWinCE）(转载)

骑猪看日落 2022-08-24 06:13 189阅读 0赞

WinCE上驱动程序的模型相对比较简单，实现一个驱动程序不是什么难事。尽管如此，本文还是实现了一个比较通用一点的通讯接口。  
  
应用程序发给信息驱动程序有两种方式，同步调用和异步调用。  
同步调用能够让驱动程序立即处理应用程序的请求，并返回驱动程序处理后的结果。  
如：  
  
\#define MSG\_TYPE\_TEST\_1 0x00000000  
\#define MSG\_TYPE\_ICMP\_PACKET 0x00000001  
  
\#pragma pack(push, 1)  
typedef struct \_\_IO\_MESSAGE  
\{  
ULONG Type;  
ULONG Length;  
  
union  
\{  
struct  
\{  
double x;  
double y;  
\}Test\_1;  
  
struct  
\{  
UCHAR MiniPacket\[128\];  
\}Icmp\_Packet;  
  
// All other messages add here  
  
\}*value*;  
\}IO\_MESSAGE, \*PIO\_MESSAGE;  
\#pragma pack(pop)  
  
\#include <windows.h>  
\#include "ioexample.h"  
\#include "ioapp.h"  
  
VOID SendMessageWithResult()  
\{  
//  
// First of all, open the device  
//  
if(!IO\_Open())  
return;  
  
  
//  
// Build message  
//  
IO\_MESSAGE Msg;  
  
Msg.Type = MSG\_TYPE\_TEST\_1;  
Msg.Length = sizeof(Msg.*value*.Test\_1);  
Msg.*value*.Test\_1.x = 3.0;  
Msg.*value*.Test\_1.y = 4.0;  
  
//  
// Call API to send, IO\_SendEx run sync and then return a result.  
//  
UCHAR lpOutBuf\[8\];  
DWORD BytesReturned;  
BOOL bRet = IO\_SendEx((PTLV)&Msg, TLV\_LENGTH(&Msg), lpOutBuf, 8, &BytesReturned);  
if(!bRet) // If return FALSE, BytesReturned is error code.  
\{  
switch(BytesReturned)  
\{  
case IO\_ERROR\_INVALID\_LENGTH:  
break;  
case IO\_ERROR\_UNKNOWN:  
break;  
\}  
\}  
  
//  
// Then we get the result  
//  
double z = \*(double\*)lpOutBuf;  
  
//  
// When we quit application, don't forget close device.  
//  
IO\_Close();  
\}  
  
异步调用不需要结果返回，调用立即返回。对驱动程序的请求会随后执行。  
如：  
  
VOID SendMsg()  
\{  
//  
// First of all, open the device  
//  
if(!IO\_Open())  
return;  
  
  
//  
// Build message  
//  
IO\_MESSAGE Msg;  
  
Msg.Type = MSG\_TYPE\_TEST\_1;  
Msg.Length = sizeof(Msg.*value*.Test\_1);  
Msg.*value*.Test\_1.x = 3.0;  
Msg.*value*.Test\_1.y = 4.0;  
  
//  
// Call API to send, IO\_SendEx run async.  
//  
BOOL bRet = IO\_Send((PTLV)&Msg, TLV\_LENGTH(&Msg)); // if we give sizeof(Msg) is also OK.  
if(!bRet) // If return FALSE, something error.  
\{  
\}  
  
//  
// When we quit application, don't forget close device.  
//  
IO\_Close();  
\}  
  
驱动程序也可以通知应用程序，应用程序检测到通知事件后，可以取回驱动程序发送给应用程序的请求。  
  
如：  
  
VOID ThreadForReceive()  
\{  
//  
// First of all, open the device  
//  
if(!IO\_Open())  
return;  
  
//  
// setup a receive event for driver  
//  
HANDLE hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);  
if(hEvent == NULL)  
return;  
  
IO\_InitializeReceiveEvent(hEvent);  
  
//  
// We can wait for this event and then receive one or more times  
//  
while(1)  
\{  
DWORD dRet = WaitForSingleObject(hEvent, INFINITE);  
if(dRet == WAIT\_OBJECT\_0)  
\{  
DWORD NumbersRemained;  
IO\_MESSAGE OutMessage;  
BOOL bRet = IO\_Receive((PTLV)&OutMessage, sizeof(IO\_MESSAGE), &NumbersRemained);  
if(bRet == FALSE) // if return false, numbersremained is error code  
\{  
\}  
else  
\{  
  
\}  
  
for(int i=0; i<NumbersRemained; i++)  
\{  
DWORD temp;  
bRet = IO\_Receive((PTLV)&OutMessage, sizeof(IO\_MESSAGE), &temp);  
\}  
\}  
  
// We can test here whether main process let us quit  
//if(WAIT\_OBJECT\_0 == WaitForSingalObject(hQuitEvent, 0))  
// break;  
  
// As a test, any way we should break here  
break;  
\}  
  
  
// Free them  
IO\_RemoveReceiveEvent();  
CloseHandle(hEvent);  
  
//  
// When we quit application, don't forget close device.  
//  
IO\_Close();  
\}