Re: [PATCH] Append to input history file instead of overwriting it

[Eli Zaretskii <eliz@gnu.org>]

> From: Patrick Palka <patrick@parcs.ath.cx>
> Cc: Patrick Palka <patrick@parcs.ath.cx>
> Date: Sat, 10 Jan 2015 10:18:28 -0500
> 
> +  local_history_filename = xstrprintf ("%s.%d", history_filename, getpid ());
> +  old_chain = make_cleanup (xfree, local_history_filename);
> +
> +  ret = rename (history_filename, local_history_filename);
> +  if (ret < 0)
> +    {
> +      /* If the rename failed then either the global history file never existed
> +         in the first place or another GDB process is currently appending to it
> +         (and has thus temporarily renamed it).  Since we can't distinguish
> +         between these two cases, we have to conservatively assume the first
> +         case and therefore must write out (not append) our known history to
> +         our local history file and try to move it back anyway.  Otherwise a
> +         global history file would never get created!  */
> +      write_history (local_history_filename);
> +    }
> +  else
> +    {
> +      append_history (command_count, local_history_filename);
> +      history_truncate_file (local_history_filename, history_max_entries);
> +    }
> +
> +  ret = rename (local_history_filename, history_filename);
> +  saved_errno = errno;
> +  if (ret < 0)
> +    warning (_("Could not rename %s to %s: error %d"),
> +	     local_history_filename, history_filename, saved_errno);
> +
> +  do_cleanups (old_chain);

On Windows, a call to 'rename' fails if the destination already
exists.  Does the logic here cope with that?

Thanks.