Re: [PATCH] fchmodat: Use /proc on Cygwin

[Ken Brown]

On 7/23/2020 5:16 PM, Bruno Haible wrote:
> Ken Brown wrote:
> > diff --git a/lib/fchmodat.c b/lib/fchmodat.c
> > index 895016860..eee0a1c56 100644
> > --- a/lib/fchmodat.c
> > +++ b/lib/fchmodat.c
> > @@ -98,7 +98,7 @@ fchmodat (int dir, char const *file, mode_t mode, int flags)
> >             return -1;
> >           }
> >   
> > -#   if defined __linux__ || defined __ANDROID__
> > +#   if defined __linux__ || defined __ANDROID__ || defined __CYGWIN__
> >         static char const fmt[] = "/proc/self/fd/%d";
> >         char buf[sizeof fmt - sizeof "%d" + INT_BUFSIZE_BOUND (int)];
> >         sprintf (buf, fmt, fd);
>
> So, chmod ("/proc/self/fd/n") works on Cygwin like on Linux. Then, we can make
> the same change also in lchmod.c.
>
>
> 2020-07-23  Bruno Haible  <bruno@clisp.org>
>
>         lchmod: Use /proc on Cygwin.
>         * lib/lchmod.c (lchmod): Use /proc on Cygwin.
>
> diff --git a/lib/lchmod.c b/lib/lchmod.c
> index e113211..77a0060 100644
> --- a/lib/lchmod.c
> +++ b/lib/lchmod.c
> @@ -76,7 +76,7 @@ lchmod (char const *file, mode_t mode)
>         return -1;
>       }
>   
> -# if defined __linux__ || defined __ANDROID__
> +# if defined __linux__ || defined __ANDROID__ || defined __CYGWIN__
>     static char const fmt[] = "/proc/self/fd/%d";
>     char buf[sizeof fmt - sizeof "%d" + INT_BUFSIZE_BOUND (int)];
>     sprintf (buf, fmt, fd);

Yes, that should work.  Can you tell me how to test it?  I've never had occasion 
to use Gnulib except indirectly, when building a project like Emacs that uses 
it.  But the Cygwin build of Emacs doesn't seem to use lchmod.

Thanks.