Re: [PATCH] qemu-options.hx: Document -M as -machine alias

[Peter Maydell <peter.maydell@linaro.org>]

On Wed, 3 Dec 2025 at 16:20, Dr. David Alan Gilbert <dave@treblig.org> wrote:
>
> * Peter Maydell (peter.maydell@linaro.org) wrote:
> > Surprisingly, this and -h/--help are our only two options where
> > we provide a short synonym. I note that this handling of -M
> > is not consistent with how we document -h/--help, where we
> > print both on a single line:
> > -h or -help     display this help and exit
> >
> > But it would be trickier to fit that in for -machine and
> > perhaps confusing given the suboptions.
>
> Right, that's one of the two reasons I kept it separate.
> The other reason, is that I couldn't figure out how '-help' and '-h'
> both got defined - why is the second DEF(...) not needed?

A piece of delicious fudge lurking in system/vl.c: we have
this hardcoded entry in the qemu_options[] array before
the ones that are generated via the macro-magic from
qemu-options.hx:

    { "h", 0, QEMU_OPTION_h, QEMU_ARCH_ALL },

So we recognize -h on the command line and turn it into
QEMU_OPTION_h, the same as -help, but it doesn't result in
anything in the documentation (we leave that up to the
strings and RST in the DEF("help"...) section).

thanks
-- PMM