Re: [Qemu-arm] [Qemu-devel] [PATCH 12/13] target/arm/arm-semi: Implement SH_EXT_STDOUT_STDERR extension

[Peter Maydell]

On Thu, 12 Sep 2019 at 13:05, Alex Bennée <address@hidden> wrote:
>
>
> Peter Maydell <address@hidden> writes:
> > +            /*
> > +             * We implement SH_EXT_STDOUT_STDERR, so:
> > +             *  open for read == stdin
> > +             *  open for write == stdout
> > +             *  open for append == stderr
> > +             */
>
> I love the way the spec documents field2 as an ISO C fopen() mode and
> then an extension literally subverts the meaning to be something else.
> Where the designers worried about adding a SYS_OPEN_TTY function to the
> interface?

It's just extending the existing convention of "open ::tt as
read for stdin and write for stdout" a bit. IIRC some existing
implementations actually did this as a sort of undocumented
extra.

thanks
-- PMM