Re: [Qemu-devel] Redundant redeclaration of 'gmtime_r' with mingw64

["Daniel P. Berrange" <berrange@redhat.com>]

On Tue, Sep 22, 2015 at 04:11:34PM +0300, Michael S. Tsirkin wrote:
> On Fri, Jun 05, 2015 at 03:38:21PM +0100, Stefan Hajnoczi wrote:
> > Hi Stefan,
> > I get the following compiler warning in Fedora 22
> > (mingw32-headers-4.0.2-1.fc22):
> > 
> > In file included from qemu/include/qemu-common.h:47:0,
> >                  from qemu/include/qemu/timer.h:5,
> >                  from qemu/include/sysemu/sysemu.h:8,
> >                  from os-win32.c:34:
> > qemu/include/sysemu/os-win32.h:77:12: warning: redundant redeclaration
> > of 'gmtime_r' [-Wredundant-decls]
> >  struct tm *gmtime_r(const time_t *timep, struct tm *result);
> >             ^
> > In file included from os-win32.c:30:0:
> > /usr/i686-w64-mingw32/sys-root/mingw/include/time.h:272:107: note:
> > previous definition of 'gmtime_r' was here
> > 
> > QEMU has its own (non-reentrant) gmtime_r() and localtime_r()
> > functions on Windows.  os-win32.h redefines the functions so the
> > compiler is right to complain.
> > 
> > I thought about adding qemu_gmtime_r() and qemu_localtime_r()
> > functions to avoid the name clash.
> > 
> > Do you have any new thoughts on this commit which introduced the
> > os-win32.h definitions?
> > 
> > commit d3e8f95753114a827f9cd8e819b1d5cc8333f76b
> > Author: Stefan Weil <sw@weilnetz.de>
> > Date:   Sat Sep 22 22:26:19 2012 +0200
> > 
> >     w32: Add implementation of gmtime_r, localtime_r
> > 
> >     Those functions are missing in MinGW.
> > 
> >     Some versions of MinGW-w64 include defines for gmtime_r and localtime_r.
> >     Older versions of these macros are buggy (they return a pointer to a
> >     static variable), therefore we don't want them. Newer versions are
> >     similar to the code used here, but without the memset.
> > 
> >     The implementation which is used here is not strictly reentrant,
> >     but sufficiently good for QEMU on w32 or w64.
> > 
> >     Signed-off-by: Stefan Weil <sw@weilnetz.de>
> >     [blauwirbel@gmail.com: added comment about locking]
> >     Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
> 
> I tried this: it compiles, but then fails to link.
> 
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

I've had a more complete patch posted several times now, still waiting
to be picked up...

https://lists.gnu.org/archive/html/qemu-devel/2015-09/msg01926.html


Regards,
Daniel
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