@msdn=http://search.microsoft.com/search/results.aspx?qu=$$$ @pinvoke=http://pinvoke.net/$$$.htm Summary: The CreateNamedPipe API !!!!C# Signature: [DllImport("kernel32.dll", SetLastError = true)] static extern IntPtr CreateNamedPipe(string lpName, uint dwOpenMode, uint dwPipeMode, uint nMaxInstances, uint nOutBufferSize, uint nInBufferSize, uint nDefaultTimeOut, IntPtr lpSecurityAttributes); !!!!User-Defined Types: [Flags] public enum PipeOpenModeFlags : uint { PIPE_ACCESS_DUPLEX = 0x00000003, PIPE_ACCESS_INBOUND = 0x00000001, PIPE_ACCESS_OUTBOUND = 0x00000002, FILE_FLAG_FIRST_PIPE_INSTANCE = 0x00080000, FILE_FLAG_WRITE_THROUGH = 0x80000000, FILE_FLAG_OVERLAPPED = 0x40000000, WRITE_DAC = 0x00040000L, WRITE_OWNER = 0x00080000L, ACCESS_SYSTEM_SECURITY = 0x01000000L } [Flags] public enum PipeModeFlags : uint { //One of the following type modes can be specified. The same type mode must be specified for each instance of the pipe. PIPE_TYPE_BYTE = 0x00000000, PIPE_TYPE_MESSAGE = 0x00000004, //One of the following read modes can be specified. Different instances of the same pipe can specify different read modes PIPE_READMODE_BYTE = 0x00000000, PIPE_READMODE_MESSAGE = 0x00000002, //One of the following wait modes can be specified. Different instances of the same pipe can specify different wait modes. PIPE_WAIT = 0x00000000, PIPE_NOWAIT = 0x00000001, //One of the following remote-client modes can be specified. Different instances of the same pipe can specify different remote-client modes. PIPE_ACCEPT_REMOTE_CLIENTS = 0x00000000, PIPE_REJECT_REMOTE_CLIENTS = 0x00000008 } !!!!Notes: http://codemortem.blogspot.com/2006/01/creating-null-dacl-in-managed-code.html - Blog post on how to populate the SECURITY_ATTRIBUTES structure from managed code. !!!!Tips & Tricks: Please add some! !!!!Sample Code: /* A complete wrapper for named pipes (both client and server sides). Yes, its overkill for this p/invoke entry, but where else should it be posted then? Les at ivsds dot com. */ using System; using System.IO; using System.Runtime.InteropServices; using System.ComponentModel; using System.Text; namespace LibDcAgent { /// <summary> /// NamedPipeStream is an odd little hybrid between the client and server ends of a NamedPipe, /// and a System.IO.Stream subclass. Basically, it simplifies the unnecessarily horrific process /// of implementing named pipe support in .Net. (If you doubt this, try it the hard way... we'll wait.) /// /// Usage idiom: /// /// Server side /// ----------- /// 1. Call NamedPipeStream.Create, specify inbound, outbound, or both /// 2. Call Listen(). This will block until a client connects. Sorry, the alternatives /// are ugly. Use a thread. /// 3. Call DataAvailable() in a loop with Read(), Write, ReadLine(), etc. until IsConnected turns false. /// 4. Call Listen() again to wait for the next client. /// /// Client side /// ----------- /// 1. Call Open() /// 2. Call DataAvailable(), Read(), Write(), etc. until you're done, /// then call Close(); /// /// And yes, you can attach TextReader and TextWriter instances to this stream. /// /// Server side caveat: /// /// The idiom described above only supports a single client at a time. If you need /// to support multiple clients, multiple calls to Create()/Listen() in separate threads is the /// recommended approach. /// /// There is a test driver class at the end of this file which can be cannibalized for sample usage code. /// /// </summary> public class NamedPipeStream : Stream { [DllImport("kernel32.dll", EntryPoint = "CreateFile", SetLastError = true)] private static extern IntPtr CreateFile(String lpFileName, UInt32 dwDesiredAccess, UInt32 dwShareMode, IntPtr lpSecurityAttributes, UInt32 dwCreationDisposition, UInt32 dwFlagsAndAttributes, IntPtr hTemplateFile); [DllImport("kernel32.dll", SetLastError = true)] private static extern IntPtr CreateNamedPipe( String lpName, // pipe name uint dwOpenMode, // pipe open mode uint dwPipeMode, // pipe-specific modes uint nMaxInstances, // maximum number of instances uint nOutBufferSize, // output buffer size uint nInBufferSize, // input buffer size uint nDefaultTimeOut, // time-out interval IntPtr pipeSecurityDescriptor // SD ); [DllImport("kernel32.dll", SetLastError = true)] private static extern bool DisconnectNamedPipe( IntPtr hHandle); [DllImport("kernel32.dll", SetLastError = true)] private static extern bool ConnectNamedPipe( IntPtr hHandle, // handle to named pipe IntPtr lpOverlapped // overlapped structure ); [DllImport("kernel32.dll", EntryPoint = "PeekNamedPipe", SetLastError = true)] private static extern bool PeekNamedPipe(IntPtr handle, byte[] buffer, uint nBufferSize, ref uint bytesRead, ref uint bytesAvail, ref uint BytesLeftThisMessage); [DllImport("kernel32.dll", SetLastError = true)] private static extern bool ReadFile(IntPtr handle, byte[] buffer, uint toRead, ref uint read, IntPtr lpOverLapped); [DllImport("kernel32.dll", SetLastError = true)] private static extern bool WriteFile(IntPtr handle, byte[] buffer, uint count, ref uint written, IntPtr lpOverlapped); [DllImport("kernel32.dll", SetLastError = true)] private static extern bool CloseHandle(IntPtr handle); [DllImport("kernel32.dll", SetLastError = true)] private static extern bool FlushFileBuffers(IntPtr handle); /*[DllImport("kernel32.dll", SetLastError = true)] private static extern uint GetLastError();*/ //Constants for dwDesiredAccess: private const UInt32 GENERIC_READ = 0x80000000; private const UInt32 GENERIC_WRITE = 0x40000000; //Constants for return value: private const Int32 INVALID_HANDLE_VALUE = -1; //Constants for dwFlagsAndAttributes: private const UInt32 FILE_FLAG_OVERLAPPED = 0x40000000; private const UInt32 FILE_FLAG_NO_BUFFERING = 0x20000000; //Constants for dwCreationDisposition: private const UInt32 OPEN_EXISTING = 3; #region Comments /// <summary> /// Outbound pipe access. /// </summary> #endregion private const uint PIPE_ACCESS_OUTBOUND = 0x00000002; #region Comments /// <summary> /// Duplex pipe access. /// </summary> #endregion private const uint PIPE_ACCESS_DUPLEX = 0x00000003; #region Comments /// <summary> /// Inbound pipe access. /// </summary> #endregion private const uint PIPE_ACCESS_INBOUND = 0x00000001; #region Comments /// <summary> /// Pipe blocking mode. /// </summary> #endregion private const uint PIPE_WAIT = 0x00000000; #region Comments /// <summary> /// Pipe non-blocking mode. /// </summary> #endregion private const uint PIPE_NOWAIT = 0x00000001; #region Comments /// <summary> /// Pipe read mode of type Byte. /// </summary> #endregion private const uint PIPE_READMODE_BYTE = 0x00000000; #region Comments /// <summary> /// Pipe read mode of type Message. /// </summary> #endregion private const uint PIPE_READMODE_MESSAGE = 0x00000002; #region Comments /// <summary> /// Byte pipe type. /// </summary> #endregion private const uint PIPE_TYPE_BYTE = 0x00000000; #region Comments /// <summary> /// Message pipe type. /// </summary> #endregion private const uint PIPE_TYPE_MESSAGE = 0x00000004; #region Comments /// <summary> /// Pipe client end. /// </summary> #endregion private const uint PIPE_CLIENT_END = 0x00000000; #region Comments /// <summary> /// Pipe server end. /// </summary> #endregion private const uint PIPE_SERVER_END = 0x00000001; #region Comments /// <summary> /// Unlimited server pipe instances. /// </summary> #endregion private const uint PIPE_UNLIMITED_INSTANCES = 255; #region Comments /// <summary> /// Waits indefinitely when connecting to a pipe. /// </summary> #endregion private const uint NMPWAIT_WAIT_FOREVER = 0xffffffff; #region Comments /// <summary> /// Does not wait for the named pipe. /// </summary> #endregion private const uint NMPWAIT_NOWAIT = 0x00000001; #region Comments /// <summary> /// Uses the default time-out specified in a call to the CreateNamedPipe method. /// </summary> #endregion private const uint NMPWAIT_USE_DEFAULT_WAIT = 0x00000000; private const ulong ERROR_PIPE_CONNECTED = 535; /// <summary> /// Server side creation option: /// </summary> public enum ServerMode { InboundOnly = (int)PIPE_ACCESS_INBOUND, OutboundOnly = (int)PIPE_ACCESS_OUTBOUND, Bidirectional = (int)(PIPE_ACCESS_INBOUND+PIPE_ACCESS_OUTBOUND) }; public enum PeerType { Client = 0, Server = 1 }; IntPtr _handle; FileAccess _mode; PeerType _peerType; protected NamedPipeStream() { _handle = IntPtr.Zero; _mode = (FileAccess)0; _peerType = PeerType.Server; } public NamedPipeStream(string pipename, FileAccess mode) { _handle = IntPtr.Zero; _peerType = PeerType.Client; Open(pipename, mode); } public NamedPipeStream(IntPtr handle, FileAccess mode) { _handle = handle; _mode = mode; _peerType = PeerType.Client; } /// <summary> /// Opens the client side of a pipe. /// </summary> /// <param name="pipe">Full path to the pipe, e.g. '\\.\pipe\mypipe'</param> /// <param name="mode">Read,Write, or ReadWrite - must be compatible with server-side creation mode</param> public void Open(string pipename, FileAccess mode) { uint pipemode = 0; if ((mode & FileAccess.Read) > 0) pipemode |= GENERIC_READ; if ((mode & FileAccess.Write) > 0) pipemode |= GENERIC_WRITE; IntPtr handle = CreateFile(pipename, pipemode, 0, IntPtr.Zero, OPEN_EXISTING, 0, IntPtr.Zero); if (handle.ToInt32() == INVALID_HANDLE_VALUE) { int err = Marshal.GetLastWin32Error(); throw new Win32Exception(err, string.Format("NamedPipeStream.Open failed, win32 error code {0}, pipename '{1}' ",err,pipename)); } _mode = mode; _handle = handle; } /// <summary> /// Create a named pipe instance. /// </summary> /// <param name="pipeName">Local name (the part after \\.\pipe\)</param> public static NamedPipeStream Create(string pipeName, ServerMode mode) { IntPtr handle = IntPtr.Zero; string name = @"\\.\pipe\" + pipeName; handle = CreateNamedPipe( name, (uint)mode, PIPE_TYPE_BYTE | PIPE_WAIT, PIPE_UNLIMITED_INSTANCES, 0, // outBuffer, 1024, // inBuffer, NMPWAIT_WAIT_FOREVER, IntPtr.Zero); if (handle.ToInt32() == INVALID_HANDLE_VALUE) { throw new Win32Exception("Error creating named pipe " + name + " . Internal error: " + Marshal.GetLastWin32Error().ToString()); } // Set members persistently... NamedPipeStream self = new NamedPipeStream(); self._handle = handle; switch (mode) { case ServerMode.InboundOnly: self._mode = FileAccess.Read; break; case ServerMode.OutboundOnly: self._mode = FileAccess.Write; break; case ServerMode.Bidirectional: self._mode = FileAccess.ReadWrite; break; } return self; } /// <summary> /// Server only: block until client connects /// </summary> /// <returns></returns> public bool Listen() { if (_peerType != PeerType.Server) throw new Exception("Listen() is only for server-side streams"); DisconnectNamedPipe(_handle); if (ConnectNamedPipe(_handle, IntPtr.Zero) != true) { uint lastErr = (uint)Marshal.GetLastWin32Error(); if (lastErr == ERROR_PIPE_CONNECTED) return true; return false; } return true; } /// <summary> /// Server only: disconnect the pipe. For most applications, you should just call Listen() /// instead, which automatically does a disconnect of any old connection. /// </summary> public void Disconnect() { if (_peerType != PeerType.Server) throw new Exception("Disconnect() is only for server-side streams"); DisconnectNamedPipe(_handle); } /// <summary> /// Returns true if client is connected. Should only be called after Listen() succeeds. /// </summary> /// <returns></returns> public bool IsConnected { get { if (_peerType != PeerType.Server) throw new Exception("IsConnected() is only for server-side streams"); if (ConnectNamedPipe(_handle, IntPtr.Zero) == false) { if ((uint)Marshal.GetLastWin32Error() == ERROR_PIPE_CONNECTED) return true; } return false; } } public bool DataAvailable { get { uint bytesRead = 0, avail = 0, thismsg = 0; bool result = PeekNamedPipe(_handle, null, 0, ref bytesRead, ref avail, ref thismsg); return (result == true && avail > 0); } } public override bool CanRead { get { return (_mode & FileAccess.Read) > 0; } } public override bool CanWrite { get { return (_mode & FileAccess.Write) > 0; } } public override bool CanSeek { get { return false; } } public override long Length { get { throw new NotSupportedException("NamedPipeStream does not support seeking"); } } public override long Position { get { throw new NotSupportedException("NamedPipeStream does not support seeking"); } set { } } public override void Flush() { if (_handle == IntPtr.Zero) throw new ObjectDisposedException("NamedPipeStream", "The stream has already been closed"); FlushFileBuffers(_handle); } public override int Read(byte[] buffer, int offset, int count) { if (buffer == null) throw new ArgumentNullException("buffer", "The buffer to read into cannot be null"); if (buffer.Length < (offset + count)) throw new ArgumentException("Buffer is not large enough to hold requested data", "buffer"); if (offset < 0) throw new ArgumentOutOfRangeException("offset", offset, "Offset cannot be negative"); if (count < 0) throw new ArgumentOutOfRangeException("count", count, "Count cannot be negative"); if (!CanRead) throw new NotSupportedException("The stream does not support reading"); if (_handle == IntPtr.Zero) throw new ObjectDisposedException("NamedPipeStream", "The stream has already been closed"); // first read the data into an internal buffer since ReadFile cannot read into a buf at // a specified offset uint read = 0; byte[] buf = buffer; if (offset != 0) { buf = new byte[count]; } bool f = ReadFile(_handle, buf, (uint)count, ref read, IntPtr.Zero); if (!f) { throw new Win32Exception(Marshal.GetLastWin32Error(), "ReadFile failed"); } if (offset != 0) { for (int x = 0; x < read; x++) { buffer[offset + x] = buf[x]; } } return (int)read; } public override void Close() { CloseHandle(_handle); _handle = IntPtr.Zero; } public override void SetLength(long length) { throw new NotSupportedException("NamedPipeStream doesn't support SetLength"); } public override void Write(byte[] buffer, int offset, int count) { if (buffer == null) throw new ArgumentNullException("buffer", "The buffer to write into cannot be null"); if (buffer.Length < (offset + count)) throw new ArgumentException("Buffer does not contain amount of requested data", "buffer"); if (offset < 0) throw new ArgumentOutOfRangeException("offset", offset, "Offset cannot be negative"); if (count < 0) throw new ArgumentOutOfRangeException("count", count, "Count cannot be negative"); if (!CanWrite) throw new NotSupportedException("The stream does not support writing"); if (_handle == IntPtr.Zero) throw new ObjectDisposedException("NamedPipeStream", "The stream has already been closed"); // copy data to internal buffer to allow writing from a specified offset if (offset != 0) { byte[] buf = new Byte[count]; for (int x = 0; x < count; x++) { buf[x] = buffer[offset + x]; } buffer = buf; } uint written = 0; bool result = WriteFile(_handle, buffer, (uint)count, ref written, IntPtr.Zero); if (!result) { int err = (int)Marshal.GetLastWin32Error(); throw new Win32Exception(err,"Writing to the stream failed"); } if (written < count) throw new IOException("Unable to write entire buffer to stream"); } public override long Seek(long offset, SeekOrigin origin) { throw new NotSupportedException("NamedPipeStream doesn't support seeking"); } } public class NamedPipeTest { /// <summary> /// Test / demo code: /// </summary> /// <param name="args"></param> public static void Main(string[] args) { if (args.Length == 0) { /* * Server-side sample code: */ NamedPipeStream stream = NamedPipeStream.Create("testpipe", NamedPipeStream.ServerMode.Bidirectional); StreamReader sr = new StreamReader(stream,Encoding.Unicode); Console.WriteLine("Listening..."); do { stream.Listen(); do { bool dataRead = false; while (stream.DataAvailable) { try { string s = sr.ReadLine(); if (s != null && s.Length > 0) { StreamWriter sw = new StreamWriter(stream, Encoding.Unicode); sw.WriteLine(s); sw.Flush(); Console.WriteLine(s); dataRead = true; } } catch { } } System.Threading.Thread.Sleep(dataRead ? 50 : 1000); } while (stream.IsConnected); } while (true); } else { /* // Client side sample code: */ NamedPipeStream stream = new NamedPipeStream(@"\\.\pipe\testpipe", FileAccess.ReadWrite); StreamWriter sw = new StreamWriter(stream, Encoding.Unicode); sw.AutoFlush = true; for (int i = 0; i < 500; i++) { sw.WriteLine("Hello world {0}", i); System.Threading.Thread.Sleep(1000); if (stream.DataAvailable) { StreamReader sr = new StreamReader(stream); Console.WriteLine(sr.ReadLine()); } } sw.Write("Final line"); sw.Close(); } } } } !!!!Alternative Managed API: Do you know one? Please contribute it! Documentation: CreateNamedPipe@msdn on MSDN
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