Re: [Qemu-devel] [PATCH v3] Support 'help' as a synonym for '?' in command line options

[Anthony Liguori <aliguori@us.ibm.com>]

Eduardo Habkost <ehabkost@redhat.com> writes:

> On Thu, Aug 09, 2012 at 10:02:22PM +0100, Peter Maydell wrote:
>> On 9 August 2012 20:25, Eduardo Habkost <ehabkost@redhat.com> wrote:
>> > On Fri, Aug 03, 2012 at 03:42:39PM -0500, Anthony Liguori wrote:
>> >> Peter Maydell <peter.maydell@linaro.org> writes:
>> >> > For command line options which permit '?' meaning 'please list the
>> >> > permitted values', add support for 'help' as a synonym, by abstracting
>> >> > the check out into a helper function.
>> 
>> >> Applied. Thanks.
>> >
>> > I just found out that this patch broke "-cpu ?dump", "-cpu ?cpuid", and
>> > "-cpu ?model":
>> 
>> These options appear to be completely undocumented. They're also pretty
>> ugly syntax and seem to be x86 specific.
>
> Agreed. I wasn't aware it was completely undocumented, I thought there
> was documentation somewhere.
>
>
>> However we can unbreak them
>> if we must with a patch like this:
>> 
>> --- a/vl.c
>> +++ b/vl.c
>> @@ -3215,7 +3215,11 @@ int main(int argc, char **argv, char **envp)
>>       */
>>      cpudef_init();
>> 
>> -    if (cpu_model && is_help_option(cpu_model)) {
>> +    /* We have to check for "starts with '?' as well as is_help_option
>> +     * to support targets which implement various weird help options
>> +     * via '?thingy' syntax.
>> +     */
>> +    if (cpu_model && (is_help_option(cpu_model) || *cpu_model == '?')) {
>>          list_cpus(stdout, &fprintf, cpu_model);
>>          exit(0);
>>      }
>> 
>> (will send as a proper patch with commit message and signoff tomorrow).
>> 
>> Any suggestions for what the sane syntax for these options would be?
>> (ie the analogous change to having '?' go to 'help').
>
> What about "-cpu help,dump" or "-cpu help=dump"?

Let's just drop the feature.  I doubt a user would ever do this.

For 1.3, I'd like to introduce glib option groups and allow for group
specific help options.  IOW, --help-cpu

Regards,

Anthony Liguori

>
> -- 
> Eduardo