How to convert a pipe handle to file_descriptor(int) for Google's protobuf

Question

I tried to use the handle hPipe as following the example here:

  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 
      0,                        // client time-out 
      NULL); 

ZeroCopyOutputStream* raw_output = new FileOutputStream(hPipe);
CodedOutputStream* coded_output = new CodedOutputStream(raw_output);

But get an error:

'google::protobuf::io::FileOutputStream::FileOutputStream(int,int)' : cannot convert parameter 1 from 'HANDLE' to 'int'

And here's the signature:

FileOutputStream(int file_descriptor, int block_size = -1);

So how to convert a handle to file_descriptor in c++?

UPDATE

I tried the recommended _open_osfhandle but seems not correct, reporting:

error C2664: '_open_osfhandle' : cannot convert parameter 1 from 'HANDLE' to 'intptr_t'

Answer 1

It sounds like what you want is _open_osfhandle.