获取Windows系统版本号以及位数（兼容Win8）

#include <WINDOWS.H>

int GetSystemVersionInfoEx(OSVERSIONINFOEX &osvi, SYSTEM_INFO &si)
{
        const int BUFSIZE = 80;
        typedef void (WINAPI *PGNSI)(LPSYSTEM_INFO);

        PGNSI pGNSI = NULL;
        BOOL bOsVersionInfoEx = FALSE;

        ZeroMemory(&si, sizeof(SYSTEM_INFO));
        ZeroMemory(&osvi, sizeof(OSVERSIONINFOEX));

        osvi.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);

        if(!(bOsVersionInfoEx = GetVersionEx ((OSVERSIONINFO*)&osvi)))
        {
                osvi.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
                if (!GetVersionEx((OSVERSIONINFO*)&osvi))
                        return GetLastError();
        }

        pGNSI = (PGNSI)GetProcAddress(GetModuleHandle(TEXT("kernel32.dll")), "GetNativeSystemInfo");

        if(NULL != pGNSI)
                pGNSI(&si);
        else
                GetSystemInfo(&si);

        return GetLastError();
}