<close> and os.exit()

[Phil Leblanc <philanc@...>]

When os.exit() is called, by default the finalizer for <close>
variables is not executed. If the second (optional) argument to
os.exit() is true, then the Lua state is closed, and finalizers are
executed.

  local x <close>
  ...
  os.exit(1)  -- x finalizer is not called
  os.exit(1, true) -- x finalizer is called

I suggest to change the default for the second exit() argument so that
the default be to call finalizers upon exit.

In special cases where the intent is ro _not_ call the finalizers, the
optional argument to exit should be set to true.

So the os.exit signature would be: os.exit ([code [, noclose]])
and the behavior would be

  os.exit(1)  -- finalizers are called (the default)
  os.exit(1, true)  -- finalizers are not called


In a way, it is the same logic as in C:

  exit(1);
       // the default behavior is to call the atexit()-registered functions.

  _exit();
       // In the special cases where atexit()-registered functions should
       // not be called, _exit() should be used instead of exit

Phil