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Date: Thu, 9 Aug 2012 22:02:22 +0100
Message-ID: <CAFEAcA-3AertMzzpF=jdC__7QAa2RKneS3OitqNDJwXetRbiPA@mail.gmail.com>
From: Peter Maydell <peter.maydell@linaro.org>
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Subject: Re: [Qemu-devel] [PATCH v3] Support 'help' as a synonym for '?' in
 command line options
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To: Eduardo Habkost <ehabkost@redhat.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>, patches@linaro.org, Michael Tokarev <mjt@tls.msk.ru>, Markus Armbruster <armbru@redhat.com>, qemu-devel@nongnu.org, Blue Swirl <blauwirbel@gmail.com>, Eric Blake <eblake@redhat.com>

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. 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').

-- PMM