Re: [Qemu-devel] [RFC PATCH v3 05/11] qemu-ga: Add Windows VSS provider to quiesce applications on fsfreeze

[Tomoki Sekiyama <tomoki.sekiyama@hds.com>]

On 5/24/13 4:54 , "Stefan Hajnoczi" <stefanha@gmail.com> wrote:


>On Thu, May 23, 2013 at 06:36:35PM +0000, Tomoki Sekiyama wrote:
>> On 5/23/13 8:22 , "Stefan Hajnoczi" <stefanha@gmail.com> wrote:
>> 
>> >On Tue, May 21, 2013 at 11:33:52AM -0400, Tomoki Sekiyama wrote:
>> >> diff --git a/qga/vss-win32.h b/qga/vss-win32.h
>> >> new file mode 100644
>> >> index 0000000..7600087
>> >> --- /dev/null
>> >> +++ b/qga/vss-win32.h
>> >> @@ -0,0 +1,85 @@
>> >> +/*
>> >> + * QEMU Guest Agent win32 VSS common declarations
>> >> + *
>> >> + * Copyright Hitachi Data Systems Corp. 2013
>> >> + *
>> >> + * Authors:
>> >> + *  Tomoki Sekiyama   <tomoki.sekiyama@hds.com>
>> >> + *
>> >> + * This work is licensed under the terms of the GNU GPL, version 2
>>or
>> >>later.
>> >> + * See the COPYING file in the top-level directory.
>> >> + */
>> >> +
>> >> +#ifndef VSS_WIN32_H
>> >> +#define VSS_WIN32_H
>> >> +
>> >> +#define __MIDL_user_allocate_free_DEFINED__
>> >> +#include "config-host.h"
>> >> +#include <windows.h>
>> >> +#include <shlwapi.h>
>> >> +
>> >> +/* Reduce warnings to include vss.h */
>> >> +#define __in  IN
>> >> +#define __out OUT
>> >> +#define __RPC_unique_pointer
>> >> +#define __RPC_string
>> >> +#define __RPC__deref_inout_opt
>> >> +#define __RPC__out
>> >> +#ifndef __RPC__out_ecount_part
>> >> +#define __RPC__out_ecount_part(x, y)
>> >> +#endif
>> >> +#define _declspec(x)
>> >> +#undef uuid
>> >> +#define uuid(x)
>> >
>> >This looks hacky.  Why are you stubbing out macros that vss.h uses?
>> 
>> Because these macros are internally defined/used by windows SDK's
>> headers and not fully covered by mingw (some of them is only
>> meaningful with Microsoft IDE), so it don't compile without
>> these define's.
>> 
>> This could be better if mingw supports these VSS headers, but
>> I have no idea how to achieve that...
>
>Please add a comment explaining this.

OK.

>BTW, did you look at the macro definitions to see if they define
>anything important?  In other words, is there a difference when compiled
>using Visual C++ where the macros actually have meaning?
>
>Stefan

They are just annotating for compiler to warn things like "this shouldn't
be NULL', or to give a hint to code generators.
I believe they don't affect compiled executable binaries.

Thanks,
Tomoki Sekiyama