命名管道是通過網絡來完成進程間的通信，它屏蔽了底層的網絡協議細節。我們在不了解網絡協議的情況下，也可以利用命名管道來實現進程間的通信。與Socket網絡通信相比，命名管道不再需要編寫身份驗證的代碼。將命名管道作為一種網絡編程方案時，它實際上建立了一個C/S通信體系，並在其中可靠的傳輸數據。命名管道服務器和客戶機的區別在於：服務器是唯一一個有權創建命名管道的進程，也只有它能接受管道客戶機的連接請求。而客戶機只能同一個現成的命名管道服務器建立連接。命名管道服務器只能在WindowsNT或Windows2000上創建，不過可以是客戶機。命名管道提供了兩種基本通信模式，字節模式和消息模式。在字節模式中，數據以一個連續的字節流的形式在客戶機和服務器之間流動。而在消息模式中，客戶機和服務器則通過一系列不連續的數據單位進行數據的收發，每次在管道上發出一條消息後，它必須作為一條完整的消息讀入。
服務端代碼流程：
1、創建命名管道：CreateNamedPipe
2、等待客戶端連接：ConnectNamedPipe
3、讀取客戶端請求數據：ReadFile
4、向客戶端回復數據：WriteFile
5、關閉連接：DisconnectNamedPipe
6、關閉管道：CloseHandle
#include "stdafx.h"
#include <windows.h>
#include <strsafe.h>
#define BUFSIZE 4096
DWORD WINAPI InstanceThread(LPVOID);
VOID GetAnswerToRequest(LPTSTR, LPTSTR, LPDWORD);
int _tmain(VOID)
{
BOOL fConnected;
DWORD dwThreadId;
HANDLE hPipe, hThread;
LPTSTR lpszPipename = TEXT("\\\\.\\pipe\\mynamedpipe");
// The main loop creates an instance of the named pipe and
// then waits for a client to connect to it. When the client
// connects, a thread is created to handle communications
// with that client, and the loop is repeated.
for (;;)
{
hPipe = CreateNamedPipe(
lpszPipename, // pipe name
PIPE_ACCESS_DUPLEX, // read/write access
PIPE_TYPE_MESSAGE | // message type pipe
PIPE_READMODE_MESSAGE | // message-read mode
PIPE_WAIT, // blocking mode
PIPE_UNLIMITED_INSTANCES, // max. instances
BUFSIZE, // output buffer size
BUFSIZE, // input buffer size
0, // client time-out
NULL); // default security attribute
if (hPipe == INVALID_HANDLE_VALUE)
{
printf("CreatePipe failed");
return 0;
}
// Wait for the client to connect; if it succeeds,
// the function returns a nonzero value. If the function
// returns zero, GetLastError returns ERROR_PIPE_CONNECTED.
fConnected = ConnectNamedPipe(hPipe, NULL) ? TRUE : (GetLastError() == ERROR_PIPE_CONNECTED);
if (fConnected)
{
// Create a thread for this client.
hThread = CreateThread(
NULL, // no security attribute
0, // default stack size
InstanceThread, // thread proc
(LPVOID) hPipe, // thread parameter
0, // not suspended
&dwThreadId); // returns thread ID
if (hThread == NULL)
{
printf("CreateThread failed");
return 0;
}
else CloseHandle(hThread);
}
else
{
// The client could not connect, so close the pipe.
CloseHandle(hPipe);
}
}
return 1;
}
DWORD WINAPI InstanceThread(LPVOID lpvParam)
{
TCHAR chRequest[BUFSIZE];
TCHAR chReply[BUFSIZE];
DWORD cbBytesRead, cbReplyBytes, cbWritten;
BOOL fSuccess;
HANDLE hPipe;
// The thread's parameter is a handle to a pipe instance.
hPipe = (HANDLE) lpvParam;
while (1)
{
// Read client requests from the pipe.
fSuccess = ReadFile(
hPipe, // handle to pipe
chRequest, // buffer to receive data
BUFSIZE*sizeof(TCHAR), // size of buffer
&cbBytesRead, // number of bytes read
NULL); // not overlapped I/O
if (! fSuccess || cbBytesRead == 0)
break;
printf((const char*)chRequest);
GetAnswerToRequest(chRequest, chReply, &cbReplyBytes);
// Write the reply to the pipe.
fSuccess = WriteFile(
hPipe, // handle to pipe
chReply, // buffer to write from
cbReplyBytes, // number of bytes to write
&cbWritten, // number of bytes written
NULL); // not overlapped I/O
if (! fSuccess || cbReplyBytes != cbWritten) break;
}
// Flush the pipe to allow the client to read the pipe's contents
// before disconnecting. Then disconnect the pipe, and close the
// handle to this pipe instance.
FlushFileBuffers(hPipe);
DisconnectNamedPipe(hPipe);
CloseHandle(hPipe);
return 1;
}
VOID GetAnswerToRequest(LPTSTR chRequest,
LPTSTR chReply, LPDWORD pchBytes)
{
_tprintf( TEXT("%s\n"), chRequest );
StringCchCopy( chReply, BUFSIZE, TEXT("Default answer from server") );
*pchBytes = (lstrlen(chReply)+1)*sizeof(TCHAR);
}
/* 何問起 hovertree.com */
客戶端代碼流程：
1、打開命名管道：CreateFile
2、等待服務端響應：WaitNamedPipe
3、切換管道為讀模式：SetNamedPipeHandleState
4、向服務端發數據：WriteFile
5、讀服務端返回的數據：ReadFile
6、關閉管道：CloseHandle
#include "stdafx.h"
#include <windows.h>
#include <conio.h>
#define BUFSIZE 512
int _tmain(int argc, TCHAR *argv[])
{
HANDLE hPipe;
LPTSTR lpvMessage=TEXT("Default message from client");
TCHAR chBuf[BUFSIZE];
BOOL fSuccess;
DWORD cbRead, cbWritten, dwMode;
LPTSTR lpszPipename = TEXT("\\\\.\\pipe\\mynamedpipe");
if( argc > 1 )
lpvMessage = argv[1];
// Try to open a named pipe; wait for it, if necessary.
while (1)
{
hPipe = CreateFile(
lpszPipename, // pipe name
GENERIC_READ | // read and write access
GENERIC_WRITE,
0, // no sharing
NULL, // default security attributes
OPEN_EXISTING, // opens existing pipe
0, // default attributes
NULL); // no template file
// Break if the pipe handle is valid.
if (hPipe != INVALID_HANDLE_VALUE)
break;
// Exit if an error other than ERROR_PIPE_BUSY occurs.
if (GetLastError() != ERROR_PIPE_BUSY)
{
printf("Could not open pipe");
return 0;
}
// All pipe instances are busy, so wait for 20 seconds.
if (!WaitNamedPipe(lpszPipename, 20000))
{
printf("Could not open pipe");
return 0;
}
}
// The pipe connected; change to message-read mode.
dwMode = PIPE_READMODE_MESSAGE;
fSuccess = SetNamedPipeHandleState(
hPipe, // pipe handle
&dwMode, // new pipe mode
NULL, // don't set maximum bytes
NULL); // don't set maximum time
if (!fSuccess)
{
printf("SetNamedPipeHandleState failed");
return 0;
} // 何問起 hovertree.com
// Send a message to the pipe server.
fSuccess = WriteFile(
hPipe, // pipe handle
lpvMessage, // message
(lstrlen(lpvMessage)+1)*sizeof(TCHAR), // message length
&cbWritten, // bytes written
NULL); // not overlapped
if (!fSuccess)
{
printf("WriteFile failed");
return 0;
}
do
{
// Read from the pipe.
fSuccess = ReadFile(
hPipe, // pipe handle
chBuf, // buffer to receive reply
BUFSIZE*sizeof(TCHAR), // size of buffer
&cbRead, // number of bytes read
NULL); // not overlapped
if (! fSuccess && GetLastError() != ERROR_MORE_DATA)
break;
_tprintf( TEXT("%s\n"), chBuf );
} while (!fSuccess); // repeat loop if ERROR_MORE_DATA
getch();
CloseHandle(hPipe);
return 0;
}
推薦：http://www.cnblogs.com/roucheng/p/vs2015cpp.html
