Interprocess communication

Question

I have an API for a game, which calls methods in a C++ dll, you can write bots for the game by modifying the DLL and calling certain methods. This is fine, except I'm not a big fan of C++, so I decided to use named pipes so I can send game events down the pipe to a client program, and send commands back - then the C++ side is just a simple framework for sending a listening on a named pipe.

I have some methods like this on the C# side of things:

private string Read()
{
 byte[] buffer = new byte[4096];
 int bytesRead = pipeStream.Read(buffer, 0, (int)4096);
 ASCIIEncoding encoder = new ASCIIEncoding();
 return encoder.GetString(buffer, 0, bytesRead);
}
private void Write(string message)
{
 ASCIIEncoding encoder = new ASCIIEncoding();
 byte[] sendBuffer = encoder.GetBytes(message);
 pipeStream.Write(sendBuffer, 0, sendBuffer.Length);
 pipeStream.Flush();
}

What would be the equivalent methods on the C++ side of things?

Answer 1

After you create the pipe and have pipe handles, you read and write using the ReadFile and WriteFile APIs: see Named Pipe Client in MSDN for a code example.

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However, I'm at loss exactly how to use them.

The "Named Pipe Client" section which I quoted above gives an example of how to use them.

For example, what are the types of all the arguments

The types of all the arguments are defined in MSDN: see ReadFile and WriteFile

how do I convert from a buffer of bytes which I presumably receive from the ReadFile method into a string and vice/versa?

You're sending the string using ASCIIEncoding, so you'll receive a string of non-Unicode characters.

You can convert that to a string, using the overload of the std::string constructor which takes a pointer to a character buffer plus a sencond parameter which specifies how many characters are in the buffer:

//chBuf and cbRead are as defined in the
//MSDN "Named Pipe Client" example code fragment
std::string received((const char*)chBuf, cbRead);

• Martin: Thanks, I understand that ReadFile and WriteFile are equivalent to pipestrea.Write/Read in my example. However, I'm at loss exactly how to use them. For example, what are the types of all the arguments, how do I convert from a buffer of bytes which I presumably receive from the ReadFile method into a string and vice/versa?
• ChrisW: I edited my answer to answer the additional questions in your comment.