匿名管道上重叠的I/O.

是否可以将重叠I/O与匿名管道一起使用？CreatePipe()没有任何指定FILE_FLAG_OVERLAPPED的方法,所以我假设ReadFile()将阻塞,即使我提供了OVERLAPPED结构.

1> 小智..：

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以下是匿名管道函数的实现,可以指定FILE_FLAG_OVERLAPPED:

/******************************************************************************\
*       This is a part of the Microsoft Source Code Samples. 
*       Copyright 1995 - 1997 Microsoft Corporation.
*       All rights reserved. 
*       This source code is only intended as a supplement to 
*       Microsoft Development Tools and/or WinHelp documentation.
*       See these sources for detailed information regarding the 
*       Microsoft samples programs.
\******************************************************************************/

/*++
Copyright (c) 1997  Microsoft Corporation
Module Name:
    pipeex.c
Abstract:
    CreatePipe-like function that lets one or both handles be overlapped
Author:
    Dave Hart  Summer 1997
Revision History:
--*/

#include 
#include 

ULONG PipeSerialNumber;

BOOL
APIENTRY
MyCreatePipeEx(
    OUT LPHANDLE lpReadPipe,
    OUT LPHANDLE lpWritePipe,
    IN LPSECURITY_ATTRIBUTES lpPipeAttributes,
    IN DWORD nSize,
    DWORD dwReadMode,
    DWORD dwWriteMode
    )

/*++
Routine Description:
    The CreatePipeEx API is used to create an anonymous pipe I/O device.
    Unlike CreatePipe FILE_FLAG_OVERLAPPED may be specified for one or
    both handles.
    Two handles to the device are created.  One handle is opened for
    reading and the other is opened for writing.  These handles may be
    used in subsequent calls to ReadFile and WriteFile to transmit data
    through the pipe.
Arguments:
    lpReadPipe - Returns a handle to the read side of the pipe.  Data
        may be read from the pipe by specifying this handle value in a
        subsequent call to ReadFile.
    lpWritePipe - Returns a handle to the write side of the pipe.  Data
        may be written to the pipe by specifying this handle value in a
        subsequent call to WriteFile.
    lpPipeAttributes - An optional parameter that may be used to specify
        the attributes of the new pipe.  If the parameter is not
        specified, then the pipe is created without a security
        descriptor, and the resulting handles are not inherited on
        process creation.  Otherwise, the optional security attributes
        are used on the pipe, and the inherit handles flag effects both
        pipe handles.
    nSize - Supplies the requested buffer size for the pipe.  This is
        only a suggestion and is used by the operating system to
        calculate an appropriate buffering mechanism.  A value of zero
        indicates that the system is to choose the default buffering
        scheme.
Return Value:
    TRUE - The operation was successful.
    FALSE/NULL - The operation failed. Extended error status is available
        using GetLastError.
--*/

{
  HANDLE ReadPipeHandle, WritePipeHandle;
  DWORD dwError;
  UCHAR PipeNameBuffer[ MAX_PATH ];

  //
  // Only one valid OpenMode flag - FILE_FLAG_OVERLAPPED
  //

  if ((dwReadMode | dwWriteMode) & (~FILE_FLAG_OVERLAPPED)) {
    SetLastError(ERROR_INVALID_PARAMETER);
    return FALSE;
  }

  //
  //  Set the default timeout to 120 seconds
  //

  if (nSize == 0) {
    nSize = 4096;
  }

  sprintf( PipeNameBuffer,
           "\\\\.\\Pipe\\RemoteExeAnon.%08x.%08x",
           GetCurrentProcessId(),
           PipeSerialNumber++
         );

  ReadPipeHandle = CreateNamedPipeA(
                       PipeNameBuffer,
                       PIPE_ACCESS_INBOUND | dwReadMode,
                       PIPE_TYPE_BYTE | PIPE_WAIT,
                       1,             // Number of pipes
                       nSize,         // Out buffer size
                       nSize,         // In buffer size
                       120 * 1000,    // Timeout in ms
                       lpPipeAttributes
                       );

  if (! ReadPipeHandle) {
    return FALSE;
  }

  WritePipeHandle = CreateFileA(
                      PipeNameBuffer,
                      GENERIC_WRITE,
                      0,                         // No sharing
                      lpPipeAttributes,
                      OPEN_EXISTING,
                      FILE_ATTRIBUTE_NORMAL | dwWriteMode,
                      NULL                       // Template file
                    );

  if (INVALID_HANDLE_VALUE == WritePipeHandle) {
    dwError = GetLastError();
    CloseHandle( ReadPipeHandle );
    SetLastError(dwError);
    return FALSE;
  }

  *lpReadPipe = ReadPipeHandle;
  *lpWritePipe = WritePipeHandle;
  return( TRUE );
}

---

Dave Hart的`MyCreatePipeEx`实现非常出色(基本上取决于Windows`CreatePipe`源代码本身),但你应该在所述实现中将`PipeSerialNumber ++`更改为`InterlockedIncrement(&PipeSerialNumber)`以避免MT代码中的竞争条件.

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哇,这种方法非常微不足道,天才也是如此:).简而言之:它使用所有Overlapped选项创建一对命名管道(使用CreateNamedPipe读取管道并使用WriteFile写入管道)并返回其句柄.

2> ChrisN..：

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号作为解释在这里,匿名管道不支持异步I/O.您需要使用命名管道.这里和这里有 MSDN上的示例代码.