Re: [RFA 09/23] Remove close cleanup

[Tom Tromey <tom@tromey.com>]

>>>>> "Pedro" == Pedro Alves <palves@redhat.com> writes:

Pedro> Patch looks good.
Pedro> The bit below made me stop for a second:
[...]


Pedro> Would the following be too clever?
Pedro>     /* Restore errno on exit to the value saved by the
Pedro>        last save() call.  Ctor saves.  */
Pedro>     struct scoped_errno_restore
[...]

Pedro>     /* Save errno and return MNSH_FS_ERROR.  */
Pedro>     auto fs_err = [&] ()
Pedro>     {
Pedro>        restore_errno.save ();
Pedro>        return MNSH_FS_ERROR;
Pedro>     };
[...]

Pedro> [It gets rid of both the scope, and the gotos.]

How about making fd_closer a template, like:

template<int (*CLOSER) (int) = close>
class fd_closer
...
  ~fd_closer ()
  {
    if (m_fd != -1)
      CLOSER (m_fd);
  }

Then in linux-namespaces.c:

/* A function like "close" that saves and restores errno.  */

static int
close_saving_fd (int fd)
{
  scoped_restore save_errno = make_scoped_restore (&errno);
  return close (fd);
}

...

  gdb::fd_closer<close_saving_errno> close_fd (fd);


This also removes the scope and the gotos.

The main plus is that it's simpler.  The main minus is that it's ad hoc.

Tom