WinCE上驅動程序的模型相對比較簡單，實現一個驅動程序不是什么難事。盡管如此，本文還是實現了一個比較通用一點的通訊接口。
應用程序發給信息驅動程序有兩種方式，同步調用和異步調用。
同步調用能夠讓驅動程序立即處理應用程序的請求，并返回驅動程序處理后的結果。
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();
}
異步調用不需要結果返回，調用立即返回。對驅動程序的請求會隨后執行。
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();
}
驅動程序也可以通知應用程序，應用程序檢測到通知事件后，可以取回驅動程序發送給應用程序的請求。
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();
}
驅動程序和應用程序之間通信
更新時間： 2007-02-02 09:39:29來源： 粵嵌教育瀏覽量：927