最近拿到一个别人的工程，是使用VS.net创建的，而我的机器上只有vs2010，于是用自带的转换工具将它转换成vs2010的工程，转换之前我就很担心，怕转换完后会出问题，但是没有办法，我实在是不想再安一个vs.net了。

转完后果不其然真出了问题，在重新build工程时，报了一大堆错误，其中第一个就是“fatal error C1189: #error : This file requires _WIN32_WINNT to be #defined at least to 0x0403. Value 0x0501 or higher is recommended”，然后看错误的来源，竟然是atlcore.h，这我就无语了，这是mfc自带的文件，出错的可能性基本上为0，于是只好去请教谷大叔，发现很多人都遇到了这个问题，看了几篇博客和帖子后，大概明白了，应该是_WIN32_WINNT这个宏对应定义的系统的版本号，如果太低的话，编译器就会认为代码无法在当前的系统上编译。

在Project Property –> Configuration Properties–> C/C++  -> Command Line的Additional Options框中输入：

/D“_WIN32_WINNT=0×0501”

如果操作系统是Windows server 2003，则上述0×0501处改为0×0502；若为Windows 7，则为0×0601。

The following table describes the preferred macros in use by the Windows header files.

Minimum system required                Macros to define Windows Server 2008                     NTDDI_VERSION >= NTDDI_LONGHORN Windows Vista                                NTDDI_VERSION >= NTDDI_VISTA Windows Server 2003 SP1                 NTDDI_VERSION >= NTDDI_WS03SP1 Windows Server 2003                     NTDDI_VERSION >= NTDDI_WS03 Windows XP SP2                          NTDDI_VERSION >= NTDDI_WINXPSP2 Windows XP SP1                          NTDDI_VERSION >= NTDDI_WINXPSP1 Windows XP                                  NTDDI_VERSION >= NTDDI_WINXP Windows 2000 SP4                        NTDDI_VERSION >= NTDDI_WIN2KSP4 Windows 2000 SP3                        NTDDI_VERSION >= NTDDI_WIN2KSP3 Windows 2000 SP2                        NTDDI_VERSION >= NTDDI_WIN2KSP2 Windows 2000 SP1                        NTDDI_VERSION >= NTDDI_WIN2KSP1 Windows 2000                                NTDDI_VERSION >= NTDDI_WIN2K

The following table describes the legacy macros in use by the Windows header files.

Minimum system required                 Macros to define Windows Server 2008                      _WIN32_WINNT>=0x0600                                                          WINVER>=0x0600 Windows Vista                            _WIN32_WINNT>=0x0600                                                      WINVER>=0x0600 Windows Server 2003                      _WIN32_WINNT>=0x0502                                                           WINVER>=0x0502 Windows XP                               _WIN32_WINNT>=0x0501                                                        WINVER>=0x0501 Windows 2000                             _WIN32_WINNT>=0x0500                                                       WINVER>=0x0500 Windows NT 4.0                           _WIN32_WINNT>=0x0400                                                        WINVER>=0x0400 Windows Me                               _WIN32_WINDOWS=0x0500                                                        WINVER>=0x0500 Windows 98                               _WIN32_WINDOWS>=0x0410                                                    WINVER>=0x0410 Windows 95                               _WIN32_WINDOWS>=0x0400                                                     WINVER>=0x0400 Internet Explorer 7.0                        _WIN32_IE>=0x0700 Internet Explorer 6.0 SP2                 _WIN32_IE>=0x0603 Internet Explorer 6.0 SP1                 _WIN32_IE>=0x0601 Internet Explorer 6.0                        _WIN32_IE>=0x0600 Internet Explorer 5.5                         _WIN32_IE>=0x0550 Internet Explorer 5.01                        _WIN32_IE>=0x0501 Internet Explorer 5.0, 5.0a, 5.0b          _WIN32_IE>=0x0500 Internet Explorer 4.01                       _WIN32_IE>=0x0401 Internet Explorer 4.0                          _WIN32_IE>=0x0400 Internet Explorer 3.0, 3.01, 3.02        _WIN32_IE>=0x0300