title: How do I create a memory-mapped file without a backing file on OSX?
body: <p>I want to use a library that uses file descriptors as the basic means to access its data. For performance reasons, I don't want to have to commit files to the disk each before I use this library's functions.</p>
  
  <p>I want to create (large) data blobs on the fly, and call into the library to send them to a server. As it stands, I have to write the file to disk, open it, pass the FD to the library, wait for it to finish, then delete the file on disk. Since I can re-create the blobs on demand (and they're not so large that they cause excessive virtual memory paging), saving them to disk buys me nothing, and incurs a large performance penalty.</p>
  
  <p>Is it possible to assign a FD to a block of data that resides only as a memory-mapped entity?</p>