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

[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?

commit d3e8f95753114a827f9cd8e819b1d5cc8333f76b
Author: Stefan Weil <address@hidden>
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 <address@hidden>
    address@hidden: added comment about locking]
    Signed-off-by: Blue Swirl <address@hidden>