title: Is possible to use Mac OS X XPC like IPC to exchange messages between processes? How?
body: <p>According to Apple, the new XPC Services API, introduced in Lion, provides a lightweight mechanism for basic interprocess communication integrated with Grand Central Dispatch (GCD) and launchd.</p>
  
  <p>It seems possible to use this API as a kind of IPC, like the POSIX IPC, however, I cannot find how to do it.</p>
  
  <p>I am trying to communicate two processes using the XPC API so I can pass messages between them but I always get a "XPC connection invalid" error in the server side. </p>
  
  <p>I don't want an XPC Service, I just want to exchange messages using a client-server architecture.</p>
  
  <p>I am using two BSD-like processes, so there is no Info.plist or whatever...</p>
  
  <p>I have been following this discussion <a href="http://lists.macosforge.org/pipermail/launchd-dev/2011-November/000982.html" rel="noreferrer">http://lists.macosforge.org/pipermail/launchd-dev/2011-November/000982.html</a> but this topic seems a bit obscure and undocumented.</p>
  
  <p>Thanks!</p>