PIPE каналы

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ATarget © (2005-05-23 20:31) [0]

Как на Delphi работать с PIPE каналами, создание канала, запись, чтение ):-( чето они совсем немонятные

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Fay © (2005-05-23 21:02) [1]

Multithreaded Pipe Server
The following example is a multithreaded pipe server. It has a main thread with a loop that creates a pipe instance and waits for a pipe client to connect. When a pipe client connects, the pipe server creates a thread to service that client and then continues to execute the loop. It is possible for a pipe client to connect successfully to the pipe instance in the interval between calls to the CreateNamedPipe and ConnectNamedPipe functions. If this happens, ConnectNamedPipe returns zero, and GetLastError returns ERROR_PIPE_CONNECTED.

The thread created to service each pipe instance reads requests from the pipe and writes replies to the pipe until the pipe client closes its handle. When this happens, the thread flushes the pipe, disconnects, closes its pipe handle, and terminates.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <windows.h>

VOID InstanceThread(LPVOID);
VOID GetAnswerToRequest(LPTSTR, LPTSTR, LPDWORD);

int xx = 0;

DWORD main(VOID)
{
BOOL fConnected;
DWORD dwThreadId;
HANDLE hPipe, hThread;
LPTSTR lpszPipename = "\\\\.\\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
PIPE_TIMEOUT, // client time-out
NULL); // no security attribute

if (hPipe == INVALID_HANDLE_VALUE)
MyErrExit("CreatePipe");

// 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
(LPTHREAD_START_ROUTINE) InstanceThread,
(LPVOID) hPipe, // thread parameter
0, // not suspended
&dwThreadId); // returns thread ID

if (hThread == NULL)
MyErrExit("CreateThread");
else
CloseHandle(hThread);

}
else
// The client could not connect, so close the pipe.
CloseHandle(hPipe);
}
return 1;
}

VOID InstanceThread(LPVOID lpvParam)
{
CHAR chRequest[BUFSIZE];
CHAR 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, // size of buffer
&cbBytesRead, // number of bytes read
NULL); // not overlapped I/O

if (! fSuccess || cbBytesRead == 0)
break;
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);
}

← →
VMcL © (2005-05-23 21:50) [2]

http://www.delphimaster.ru/articles/named_pipes/index.html

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ATarget © (2005-05-25 15:54) [3]

Спасибо :)

У меня на сайте в примере MSSQLAlert используются NamedPipes, там и класс есть соответствующий.

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