title: Trying to share memory in windows across multiple processes, multple languages
body: <p>I have an application where I have 3 different processes that need to run concurrently, in 3 different languages, on Windows:</p>
  
  <ul>
  <li>A "data gathering" process, which interfaces with a sensor array.  The developers of the sensor array have been kind enough to provide us with their C# source code, which I can modify.  This should be generating raw data and shoving it into shared memory</li>
  <li>A "post-processing" process.  This is C++ code that uses CUDA to get the processing done as fast as possible.  This should be taking raw data, moving it to the GPU, then taking the results from the GPU and communicating it to--</li>
  <li>A feedback controller written in Matlab, which takes the results of the post-processing and uses it to make decisions on how to control a mechanical system.</li>
  </ul>
  
  <p>I've done coursework on parallel programming, but that coursework all worked in Linux, where I used the <code>mmap.h</code> for coordination between multiple processes.  This makes sense to me--you ask the OS for a page in virtual memory to be mapped to shared physical memory addresses, and the OS gives you some shared memory.</p>
  
  <p>Googling around, it seems like the preferred way to set up shared memory between processes in Windows (in fact, the only "easy" way to do it in Matlab) is to use memory-mapped files, but this seems completely bonkers to me.  If I'm understanding correctly, a memory-mapped file grabs some disk space and maps it to the physical address space, which is then mapped into the virtual address space for any process that accesses the same memory-mapped file.  </p>
  
  <p>This seems about three times more complex than it needs to be just to get multiple processes to map pages in their virtual address space to the same physical memory.  I don't feel like I should be doing anything remotely related to disk I/O for what I'm trying to accomplish, especially since performance is a big issue for me (ideally I should be able to process 1000 sets of data per second, though that's not a hard limit).  Is this really the right way to coordinate my processes?</p>