CAnonymousPipe - Anonymous Pipe Implementation

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Introduction

Welcome to CAnonymousPipe v1.0, A freeware MFC class to encapsulate the anonymous Pipe IPC method as provided in Win32.

Features

Usage

History

API Reference

Planned Enhancements

Contacting the Author

Features

• Simple and clean C++ interface.
• The classes are fully Unicode compliant and include Unicode built options in the workspace file.

Usage

• To use the class in your code simply include apipe.cpp in your project and #include apipe.h in which ever of your modules needs to make calls to the class.
• Your code will need to include MFC either statically or dynamically.

History

v1.0 (3 August 1998)

• Initial public release.

API Reference

The API consists of the class CAnonymousPipe and its public member functions:

CAnonymousPipe
~CAnonymousPipe
Create
Close
Write
Read
Peek
IsOpen
AssertValid
Dump

CAnonymousPipe::CAnonymousPipe

CAnonymousPipe();

Remarks:
Standard default constructor. Initialises the pipe handles to a default value.

See Also:
~CAnonymousPipe

CAnonymousPipe::~CAnonymousPipe

~CAnonymousPipe();

Remarks:
Standard default destructor. Will close any pipe handles which are still open.

See Also:
CAnonymousPipe

CAnonymousPipe::Create

BOOL Create(LPSECURITY_ATTRIBUTES lpPipeAttributes = NULL, DWORD dwSize = 0);

Return Value:
Non-Zero if the anonymous pipe was successfully created otherwise FALSE. Use GetLastError() to get extended error information.

Parameters:

• lpSecurityAttributes -- Pointer to a SECURITY_ATTRIBUTES structure that specifies a security descriptor for the new anonymous pipe and determines whether child processes can inherit the returned handle. If lpSecurityAttributes is NULL, the named pipe gets a default security descriptor and the handle cannot be inherited.
• nSize -- Specifies the buffer size for the pipe. The size is only a suggestion; the system uses the value to calculate an appropriate buffering mechanism. If this parameter is zero, the system uses the default buffer size.

Remarks:
Creates an anonymous server side pipe. Unlike named pipes this function will work on non NT platforms including Windows 95 and Windows 98.

CAnonymousPipe::Close

BOOL Close();

Return Value:
Non zero if the anonymous pipe was closed otherwise FALSE. Use GetLastError() to get extended error information.

Remarks:
Closes the pipe.

CAnonymousPipe::Write

BOOL Write(LPCVOID lpBuffer, DWORD dwNumberOfBytesToWrite, DWORD& dwNumberOfBytesWritten);

Return Value:
Non zero if the write succeeded otherwise FALSE. Use GetLastError() to get extended error information.

Parameters:

• lpBuffer -- Points to the buffer containing the data to be written to the pipe.
• dwNumberOfBytesToWrite -- Specifies the number of bytes to write to the pipe.
• dwNumberOfBytesWritten -- Points to the number of bytes written by this function call. Write() sets this value to zero before doing any work or error checking.

Remarks:
Performs a write to the anonymous pipe in a synchronous manner.

CAnonymousPipe::Read

BOOL Read(LPVOID lpBuffer, DWORD dwNumberOfBytesToRead, DWORD& dwNumberOfBytesRead);

Return Value:
Non zero if the read succeeded otherwise FALSE. Use GetLastError() to get extended error information.

Parameters:

• lpBuffer -- Points to the buffer to receive the data to be read.
• dwNumberOfBytesToRead -- Specifies the number of bytes to read from the pipe.
• dwNumberOfBytesRead -- Points to the number of bytes read by this function call. Read sets this value to zero before doing any work or error checking.

Remarks:
Performs a read from the anonymous pipe in a synchronous manner.

CAnonymousPipe::Peek

BOOL Peek(LPVOID lpBuffer, DWORD dwBufferSize, DWORD& dwBytesRead, DWORD& dwTotalBytesAvail, DWORD& dwBytesLeftThisMessage);

Return Value:
Non zero if the function succeeds otherwise FALSE. Use GetLastError() to get extended error information.

Parameters:

• lpBuffer -- Points to a buffer that receives data read from the pipe. This parameter can be NULL if no data is to be read.
• dwBufferSize -- Specifies the size, in bytes, of the buffer specified by the lpBuffer parameter. This parameter is ignored if lpBuffer is NULL.
• dwBytesRead -- 32-bit variable that receives the number of bytes read from the pipe.
• dwTotalBytesAvail -- 32-bit variable that receives the total number of bytes available to be read from the pipe.
• dwBytesLeftThisMessage -- 32-bit variable that receives the number of bytes remaining in this message. This parameter will be zero for byte-type named pipes.

Remarks:
Copies data from the pipe into a buffer without removing it from the pipe. It also returns information about data in the pipe.

CAnonymousPipe::IsOpen

BOOL IsOpen() const;

Return Value:
Non zero if the pipe is open otherwise FALSE.

CAnonymousPipe::AssertValid

virtual void AssertValid();

Remarks:
Standard MFC override which performs a validity check on this instance.

CAnonymousPipe::Dump

virtual void Dump(CDumpContext& dc) const;

Parameters:

• dc -- The diagnostic dump context for dumping, usually afxDump.

Remarks:
Standard MFC override which performs a dump to the dump context as provided by dc.

Planned Enhancements

• Package the code up into an OCX to allow non MFC apps to use the code.
• Provide a sample application with the code :>)
• If you have any other suggested improvements, please let me know so that I can incorporate them into the next release.

Contacting the Author

PJ Naughter
Email: pjn@indigo.ie
Web: http://www.naughter.com
2 August 1998