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

[Stefan Hajnoczi]

On Fri, Jun 05, 2015 at 07:18:53PM +0200, Stefan Weil wrote:
> Am 05.06.2015 um 16:38 schrieb Stefan Hajnoczi:
> >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?
> 
> The version provided by Debian Jessie (mingw-w64 3.2.0)
> still uses macros to implement those functions - that's why
> I don't see that compiler warnings.
> 
> I'd prefer a solution which conditionally includes the QEMU
> declaration (include/sysemu/os-win32.h) and the implementation
> (util/oslib-win32.c), either depending on the mingw-w64 version
> or on the result of a configuration check done while running
> configure.

Does that mean you want:

1. gmtime() is a macro - use QEMU implementation
2. gmtime() is a function - use mingw function
3. gmtime() is undefined - use QEMU implementation

?

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