It's been a while now and I don't remember the details, sorry. To the best of my recollection, the BEAM VM won't do a blocking select(2). Or maybe it forces use

It's been a while now and I don't remember the details, sorry. To the best of my recollection, the BEAM VM won't do a blocking select(2). Or maybe it forces use of poll(2) when cross-compiling? Basically, the gist is that it breaks the BEAM scheduler to block on I/O for longer than a very short time, and the file read code is pretty deeply internal, so you just can't do it (network sockets are a very special exception). You can poll a file (that is, repeated reads), but you can't block and wait for, e.g. sysfs_notify. Since all Erlang threads are green threads, there's no way to accomplish a blocking read within the auspices of the VM. Thus, the C node. My goal was to reduce the time between (physical) interrupt and Erlang thread response because I was trying to make sure I didn't miss an event.