Re: [gentoo-dev] [PATCH 1/2] Introduce multibuild_merge_root() to merge interim installs.

[Michał Górny]

On Sat, 23 Mar 2013 10:44:59 -0700
Alec Warner <antarus@g.o> wrote:

> On Sat, Mar 23, 2013 at 9:26 AM, Michał Górny <mgorny@g.o> wrote:
> > +               if [[ ${lock_fd} ]]; then
> > +                       # Close the lock file when we are done with it.
> > +                       # Prevents deadlock if we aren't in a subshell.
> > +                       eval "exec ${lock_fd}>&-"
>
> Not following this bit.
>
> The bash manpage says N>&DIGIT- redirects fd DIGIT to fd N. N may be
> unspecified and defaults to 1.
> It doesn't say what happens if DIGIT is unspecified.

Hm, that's interesting. It looks like they forgot to document it. I've
just tested it with bash-3.2 and it works as expected.

> Nor does it say it closes any file descriptors.

Well, if we assume that this fragment is correct, then it does:

  DIGIT is closed after being duplicated to N.


There's also the following in bash-4.2 info page:

  If >&- or <&- is preceded by {VARNAME}, the value of VARNAME defines
  the file descriptor to close.

But IMO it's more like describing a specific case, rather than introducing
>&-.

-- 
Best regards,
Michał Górny