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

[Amos Kong]

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?

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.