Re: [Qemu-devel] [PATCH] monitor: introduce query-config-schema command

[Luiz Capitulino]

On Thu, 25 Apr 2013 11:52:58 +0800
Amos Kong <address@hidden> wrote:

> On Wed, Apr 24, 2013 at 01:39:08PM -0600, Eric Blake wrote:
> > On 04/24/2013 12:20 PM, Luiz Capitulino wrote:
> > > On Thu, 25 Apr 2013 01:33:24 +0800
> > > Amos Kong <address@hidden> wrote:
> > > 
> > >> Libvirt has no way to probe if an option or property is supported,
> > >> This patch introdues a new qmp command to query configuration schema
> > >> information. hmp command isn't added because it's not needed.
> > >>
> > >> V2: fix jaso schema and comments (Eric)
> 
> ...
> 
> > >> +#
> > >> +# @flag: If no value is given, the flag is set to 1. Otherwise the 
> > >> value must
> > >> +#        be "on" (set to 1) or "off" (set to 0)
> > > 
> > > Let's call this 'boolean', because it's what it is. Also, I suggest
> > > 'Accepts "on" or "off"' as the help text.
> > 
> > I'm fine with calling the enum value 'boolean' even where the C code
> > called it 'flag'.  As long as we have a documented name that describes
> > the semantics of what the parameter will take, libvirt should be able to
> > cope.
> > 
> > One other concern - you document that if a flag parameter is omitted,
> > then it defaults to 1.  Is that really true?
> 
> 
> I'm wrong. If it's omitted in cmdline, we will give it a default value.
> 
> example:
>    enable_mlock = qemu_opt_get_bool(opts, "mlock", true);
> 
> another example:
>    -boot strict=on
> 
>    bool boot_strict; (false by default)
> 
>    strict boot is disabled by default, type of strict parameter is 
> 'QEMU_OPT_STRING'
>    the logical default parameter is "off".
> 
> This kind of default info is only added in help descriptions right
> now, we can add a new item 'default_value' to option.h:QemuOptDesc &
> qapi-schema.json:CommandLineParameterInfo in future?

Yes. I don't think we'll have enough time to fix this now.

> 
> I guess the default value is useful for libvirt.
> 
> However, we live in different timezone, so I will post my latest patch
> to maillist (no change about default value).
> 
> Agree with other comments, thanks.
> 
> 
>                 Amos.
>