완료 루틴을 사용하는 명명된 파이프 서버
다음 예제는 메시지 형식 파이프를 만들고 겹치는 작업을 사용하는 단일 스레드 파이프 서버입니다. ReadFileEx및 WriteFileEx확장 함수를 사용하여 작업이 완료되면 실행을 위해 대기 중인 완료 루틴을 사용하여 겹치는 I/O를 수행합니다. 파이프 서버는 완료 루틴이 실행될 준비가 되면 반환되는 경고 가능 대기 작업을 수행하는 WaitForSingleObjectEx 함수를 사용합니다. 또한 대기 함수는 이벤트 개체가 신호를 받으면 반환됩니다. 이 예제에서는 겹치는 ConnectNamedPipe 작업이 완료되었음을 나타냅니다(새 클라이언트가 연결됨). 이 파이프 서버는 명명된 파이프 클라이언트에 설명된 파이프 클라이언트와 함께 사용할 수 있습니다.
처음에 파이프 서버는 파이프의 단일 인스턴스를 만들고 겹치는 ConnectNamedPipe 작업을 시작합니다. 클라이언트가 연결되면 서버는 해당 파이프 인스턴스에 대한 스토리지를 제공하는 구조를 할당한 다음 ReadFileEx 함수를 호출하여 클라이언트와의 통신을 처리하는 일련의 I/O 작업을 시작합니다. 각 작업은 시퀀스에서 다음 작업을 수행하는 완료 루틴을 지정합니다. 클라이언트의 연결이 끊어지고 파이프 인스턴스가 닫혀 있으면 시퀀스가 종료됩니다. 새 클라이언트에 대한 작업 시퀀스를 시작한 후 서버는 다른 파이프 인스턴스를 만들고 다음 클라이언트가 연결되기를 기다립니다.
ReadFileEx 및 WriteFileEx 함수의 매개 변수는 완료 루틴과 OVERLAPPED 구조에 대한 포인터를 지정합니다. 이 포인터는 lpOverLap 매개 변수의 완료 루틴에 전달됩니다. OVERLAPPED 구조체는 각 파이프 인스턴스에 할당된 구조체의 첫 번째 멤버를 가리키므로 완료 루틴은 해당 lpOverLap 매개 변수를 사용하여 파이프 인스턴스의 구조에 액세스할 수 있습니다.
#include <windows.h>
#include <stdio.h>
#include <tchar.h>
#include <strsafe.h>
#define PIPE_TIMEOUT 5000
#define BUFSIZE 4096
typedef struct
{
OVERLAPPED oOverlap;
HANDLE hPipeInst;
TCHAR chRequest[BUFSIZE];
DWORD cbRead;
TCHAR chReply[BUFSIZE];
DWORD cbToWrite;
} PIPEINST, *LPPIPEINST;
VOID DisconnectAndClose(LPPIPEINST);
BOOL CreateAndConnectInstance(LPOVERLAPPED);
BOOL ConnectToNewClient(HANDLE, LPOVERLAPPED);
VOID GetAnswerToRequest(LPPIPEINST);
VOID WINAPI CompletedWriteRoutine(DWORD, DWORD, LPOVERLAPPED);
VOID WINAPI CompletedReadRoutine(DWORD, DWORD, LPOVERLAPPED);
HANDLE hPipe;
int _tmain(VOID)
{
HANDLE hConnectEvent;
OVERLAPPED oConnect;
LPPIPEINST lpPipeInst;
DWORD dwWait, cbRet;
BOOL fSuccess, fPendingIO;
// Create one event object for the connect operation.
hConnectEvent = CreateEvent(
NULL, // default security attribute
TRUE, // manual reset event
TRUE, // initial state = signaled
NULL); // unnamed event object
if (hConnectEvent == NULL)
{
printf("CreateEvent failed with %d.\n", GetLastError());
return 0;
}
oConnect.hEvent = hConnectEvent;
// Call a subroutine to create one instance, and wait for
// the client to connect.
fPendingIO = CreateAndConnectInstance(&oConnect);
while (1)
{
// Wait for a client to connect, or for a read or write
// operation to be completed, which causes a completion
// routine to be queued for execution.
dwWait = WaitForSingleObjectEx(
hConnectEvent, // event object to wait for
INFINITE, // waits indefinitely
TRUE); // alertable wait enabled
switch (dwWait)
{
// The wait conditions are satisfied by a completed connect
// operation.
case 0:
// If an operation is pending, get the result of the
// connect operation.
if (fPendingIO)
{
fSuccess = GetOverlappedResult(
hPipe, // pipe handle
&oConnect, // OVERLAPPED structure
&cbRet, // bytes transferred
FALSE); // does not wait
if (!fSuccess)
{
printf("ConnectNamedPipe (%d)\n", GetLastError());
return 0;
}
}
// Allocate storage for this instance.
lpPipeInst = (LPPIPEINST) GlobalAlloc(
GPTR, sizeof(PIPEINST));
if (lpPipeInst == NULL)
{
printf("GlobalAlloc failed (%d)\n", GetLastError());
return 0;
}
lpPipeInst->hPipeInst = hPipe;
// Start the read operation for this client.
// Note that this same routine is later used as a
// completion routine after a write operation.
lpPipeInst->cbToWrite = 0;
CompletedWriteRoutine(0, 0, (LPOVERLAPPED) lpPipeInst);
// Create new pipe instance for the next client.
fPendingIO = CreateAndConnectInstance(
&oConnect);
break;
// The wait is satisfied by a completed read or write
// operation. This allows the system to execute the
// completion routine.
case WAIT_IO_COMPLETION:
break;
// An error occurred in the wait function.
default:
{
printf("WaitForSingleObjectEx (%d)\n", GetLastError());
return 0;
}
}
}
return 0;
}
// CompletedWriteRoutine(DWORD, DWORD, LPOVERLAPPED)
// This routine is called as a completion routine after writing to
// the pipe, or when a new client has connected to a pipe instance.
// It starts another read operation.
VOID WINAPI CompletedWriteRoutine(DWORD dwErr, DWORD cbWritten,
LPOVERLAPPED lpOverLap)
{
LPPIPEINST lpPipeInst;
BOOL fRead = FALSE;
// lpOverlap points to storage for this instance.
lpPipeInst = (LPPIPEINST) lpOverLap;
// The write operation has finished, so read the next request (if
// there is no error).
if ((dwErr == 0) && (cbWritten == lpPipeInst->cbToWrite))
fRead = ReadFileEx(
lpPipeInst->hPipeInst,
lpPipeInst->chRequest,
BUFSIZE*sizeof(TCHAR),
(LPOVERLAPPED) lpPipeInst,
(LPOVERLAPPED_COMPLETION_ROUTINE) CompletedReadRoutine);
// Disconnect if an error occurred.
if (! fRead)
DisconnectAndClose(lpPipeInst);
}
// CompletedReadRoutine(DWORD, DWORD, LPOVERLAPPED)
// This routine is called as an I/O completion routine after reading
// a request from the client. It gets data and writes it to the pipe.
VOID WINAPI CompletedReadRoutine(DWORD dwErr, DWORD cbBytesRead,
LPOVERLAPPED lpOverLap)
{
LPPIPEINST lpPipeInst;
BOOL fWrite = FALSE;
// lpOverlap points to storage for this instance.
lpPipeInst = (LPPIPEINST) lpOverLap;
// The read operation has finished, so write a response (if no
// error occurred).
if ((dwErr == 0) && (cbBytesRead != 0))
{
GetAnswerToRequest(lpPipeInst);
fWrite = WriteFileEx(
lpPipeInst->hPipeInst,
lpPipeInst->chReply,
lpPipeInst->cbToWrite,
(LPOVERLAPPED) lpPipeInst,
(LPOVERLAPPED_COMPLETION_ROUTINE) CompletedWriteRoutine);
}
// Disconnect if an error occurred.
if (! fWrite)
DisconnectAndClose(lpPipeInst);
}
// DisconnectAndClose(LPPIPEINST)
// This routine is called when an error occurs or the client closes
// its handle to the pipe.
VOID DisconnectAndClose(LPPIPEINST lpPipeInst)
{
// Disconnect the pipe instance.
if (! DisconnectNamedPipe(lpPipeInst->hPipeInst) )
{
printf("DisconnectNamedPipe failed with %d.\n", GetLastError());
}
// Close the handle to the pipe instance.
CloseHandle(lpPipeInst->hPipeInst);
// Release the storage for the pipe instance.
if (lpPipeInst != NULL)
GlobalFree(lpPipeInst);
}
// CreateAndConnectInstance(LPOVERLAPPED)
// This function creates a pipe instance and connects to the client.
// It returns TRUE if the connect operation is pending, and FALSE if
// the connection has been completed.
BOOL CreateAndConnectInstance(LPOVERLAPPED lpoOverlap)
{
LPTSTR lpszPipename = TEXT("\\\\.\\pipe\\mynamedpipe");
hPipe = CreateNamedPipe(
lpszPipename, // pipe name
PIPE_ACCESS_DUPLEX | // read/write access
FILE_FLAG_OVERLAPPED, // overlapped mode
PIPE_TYPE_MESSAGE | // message-type pipe
PIPE_READMODE_MESSAGE | // message read mode
PIPE_WAIT, // blocking mode
PIPE_UNLIMITED_INSTANCES, // unlimited instances
BUFSIZE*sizeof(TCHAR), // output buffer size
BUFSIZE*sizeof(TCHAR), // input buffer size
PIPE_TIMEOUT, // client time-out
NULL); // default security attributes
if (hPipe == INVALID_HANDLE_VALUE)
{
printf("CreateNamedPipe failed with %d.\n", GetLastError());
return 0;
}
// Call a subroutine to connect to the new client.
return ConnectToNewClient(hPipe, lpoOverlap);
}
BOOL ConnectToNewClient(HANDLE hPipe, LPOVERLAPPED lpo)
{
BOOL fConnected, fPendingIO = FALSE;
// Start an overlapped connection for this pipe instance.
fConnected = ConnectNamedPipe(hPipe, lpo);
// Overlapped ConnectNamedPipe should return zero.
if (fConnected)
{
printf("ConnectNamedPipe failed with %d.\n", GetLastError());
return 0;
}
switch (GetLastError())
{
// The overlapped connection in progress.
case ERROR_IO_PENDING:
fPendingIO = TRUE;
break;
// Client is already connected, so signal an event.
case ERROR_PIPE_CONNECTED:
if (SetEvent(lpo->hEvent))
break;
// If an error occurs during the connect operation...
default:
{
printf("ConnectNamedPipe failed with %d.\n", GetLastError());
return 0;
}
}
return fPendingIO;
}
VOID GetAnswerToRequest(LPPIPEINST pipe)
{
_tprintf( TEXT("[%d] %s\n"), pipe->hPipeInst, pipe->chRequest);
StringCchCopy( pipe->chReply, BUFSIZE, TEXT("Default answer from server") );
pipe->cbToWrite = (lstrlen(pipe->chReply)+1)*sizeof(TCHAR);
}
관련 항목