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Re: [Qemu-devel] [PATCH v2 REPOST] oslib-win32: only provide localtime_r
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] [PATCH v2 REPOST] oslib-win32: only provide localtime_r/gmtime_r if missing |
Date: |
Wed, 23 Sep 2015 09:33:24 +0100 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Tue, Sep 22, 2015 at 07:49:40PM +0200, Stefan Weil wrote:
> Hi,
>
> I suggest cleaning some comments, mostly using the "official"
> spellings for MinGW and Mingw-w64.
>
> Am 22.09.2015 um 16:13 schrieb Daniel P. Berrange:
> > The oslib-win32 file currently provides a localtime_r and
> > gmtime_r replacement unconditionally. Some versions of
> > Mingw64 would provide crude macros for localtime_r/gmtime_r
>
> MinGW / Mingw-w64
>
> > which QEMU takes care to disable. Latest versions of Mingw64
>
> Mingw-w64
>
> > now provide actual functions for localtime_r/gmtime_r, but
> > with a twist that you have to include unistd.h or pthread.h
> > before including time.h. By luck some files in QEMU have
> > such an include order, resulting in compile errors:
> >
> > CC util/osdep.o
> > In file included from include/qemu-common.h:48:0,
> > from util/osdep.c:48:
> > include/sysemu/os-win32.h:77:12: error: redundant redeclaration of
> > 'gmtime_r' [-Werror=redundant-decls]
> > struct tm *gmtime_r(const time_t *timep, struct tm *result);
> > ^
> > In file included from include/qemu-common.h:35:0,
> > from util/osdep.c:48:
> > /usr/i686-w64-mingw32/sys-root/mingw/include/time.h:272:107: note: previous
> > definition of 'gmtime_r' was here
> > In file included from include/qemu-common.h:48:0,
> > from util/osdep.c:48:
> > include/sysemu/os-win32.h:79:12: error: redundant redeclaration of
> > 'localtime_r' [-Werror=redundant-decls]
> > struct tm *localtime_r(const time_t *timep, struct tm *result);
> > ^
> > In file included from include/qemu-common.h:35:0,
> > from util/osdep.c:48:
> > /usr/i686-w64-mingw32/sys-root/mingw/include/time.h:269:107: note: previous
> > definition of 'localtime_r' was here
> >
> > This change adds a configure test to see if localtime_r
> > exits, and only enables the QEMU impl if missing. We also
> > re-arrange qemu-common.h try attempt to guarantee that all
> > source files get unistd.h before time.h and thus see the
> > localtime_r/gmtime_r defs.
> >
> > Signed-off-by: Daniel P. Berrange <address@hidden>
> > ---
> > configure | 34 ++++++++++++++++++++++++++++++++++
> > include/qemu/osdep.h | 4 +++-
> > include/sysemu/os-win32.h | 2 ++
> > util/oslib-win32.c | 2 ++
> > 4 files changed, 41 insertions(+), 1 deletion(-)
> >
> > diff --git a/configure b/configure
> > index 52f5b79..4654be8 100755
> > --- a/configure
> > +++ b/configure
> > @@ -1737,6 +1737,37 @@ else
> > fi
> >
> > ##########################################
> > +# Mingw64 localtime_r/gmtime_r check
>
> MinGW / Mingw-w64
>
> > +
> > +if test "$mingw32" = "yes"; then
> > + # Some versions of Mingw32/64 lack localtime_r
>
> MinGW / Mingw-w64
>
> > + # and gmtime_r entirely
>
> Missing .
>
> > + #
> > + # Some versions of Mingw64 define a macro for
>
> Mingw-w64
>
> > + # localtime_r/gmtime_r/etc
>
> Why etc? Missing .
They also define macros for some other functions, but they
don't cause us problems, so we're not dealing with them
here. Simpler to just remove the /etc though.
>
> > + #
> > + # Some versions of Ming64 will define functions
> > + # for localtime_r/gmtime_r, but only if you have
> > + # _POSIX_THREAD_SAFE_FUNCTIONS defined. For fun
> > + # though, unistd.h and pthread.h both define
> > + # that for you.
> > + #
> > + # So this #undef localtime_r and #include <unistd.h>
> > + # are not in fact redundant
>
>
> Otherwise this patch looks good.
>
> If you agree, I'd clean the comments before I add
> the patch to my patch queue for Windows
> (git://qemu.weilnetz.de/qemu.git wxx).
Yes, I'm fine with you applying it to your queue and adding the fixes
mentioned.
Regards,
Daniel
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