Re: [Qemu-devel] [PATCH v2 3/3] util: remove redundant include of glib.h

From: Markus Armbruster <armbru@redhat.com>
To: Peter Xu <peterx@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>,
	Olaf Hering <olaf@aepfle.de>,
	Stefan Berger <stefanb@linux.vnet.ibm.com>,
	Michael Roth <mdroth@linux.vnet.ibm.com>,
	QEMU Developers <qemu-devel@nongnu.org>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Thomas Huth <thuth@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v2 3/3] util: remove redundant include of glib.h
Date: Thu, 07 Jun 2018 09:05:28 +0200	[thread overview]
Message-ID: <878t7r3wlj.fsf@dusky.pond.sub.org> (raw)
In-Reply-To: <20180607035805.GH7815@xz-mi> (Peter Xu's message of "Thu, 7 Jun 2018 11:58:05 +0800")

Peter Xu <peterx@redhat.com> writes:

> On Wed, Jun 06, 2018 at 07:31:53PM +0100, Peter Maydell wrote:
>> On 6 June 2018 at 18:32, Daniel P. Berrangé <berrange@redhat.com> wrote:
>> > Code must only ever include glib.h indirectly via the glib-compat.h
>> > header file, because we will need some macros set before glib.h is
>> > pulled in. Adding extra includes of glib.h will (soon) cause compile
>> > failures such as:
>> >
>> > In file included from /home/berrange/src/virt/qemu/include/qemu/osdep.h:107,
>> >                  from /home/berrange/src/virt/qemu/include/qemu/iova-tree.h:26,
>> >                  from util/iova-tree.c:13:
>> > /home/berrange/src/virt/qemu/include/glib-compat.h:22: error: "GLIB_VERSION_MIN_REQUIRED" redefined [-Werror]
>> >  #define GLIB_VERSION_MIN_REQUIRED GLIB_VERSION_2_40
>> >
>> > In file included from /usr/include/glib-2.0/glib/gtypes.h:34,
>> >                  from /usr/include/glib-2.0/glib/galloca.h:32,
>> >                  from /usr/include/glib-2.0/glib.h:30,
>> >                  from util/iova-tree.c:12:
>> > /usr/include/glib-2.0/glib/gversionmacros.h:237: note: this is the location of the previous definition
>> >  # define GLIB_VERSION_MIN_REQUIRED      (GLIB_VERSION_CUR_STABLE)
>> >
>> > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
>> > ---
>> >  util/iova-tree.c | 1 -
>> >  1 file changed, 1 deletion(-)
>> >
>> > diff --git a/util/iova-tree.c b/util/iova-tree.c
>> > index 2d9cebfc89..d39cd8bb29 100644
>> > --- a/util/iova-tree.c
>> > +++ b/util/iova-tree.c
>> > @@ -9,7 +9,6 @@
>> >   * This work is licensed under the terms of the GNU GPL, version 2 or later.
>> >   */
>> >
>> > -#include <glib.h>
>> >  #include "qemu/iova-tree.h"
>> 
>> While we're fixing up the headers in this file:
>> it should start with an include of qemu/osdep.h,
>> and qemu/iova-tree.h should not include osdep.h...
>
> Sorry to messed this up.  It was used for hwaddr definition.
>
> Maybe we can just replace hwaddr usage in iova-tree.[ch] with
> something like uint64_t?  Then I think we can drop the osdep.h.

Every compilation unit must include "osdep.h" first.  Its file comment
explains why.  If it's insufficiently convincing, we should fix it :)