C++ compiling on Windows and Linux: ifdef switch

I know it is not answer but added if someone looking same in Qt

In Qt

https://wiki.qt.io/Get-OS-name-in-Qt

QString Get::osName()
{
#if defined(Q_OS_ANDROID)
    return QLatin1String("android");
#elif defined(Q_OS_BLACKBERRY)
    return QLatin1String("blackberry");
#elif defined(Q_OS_IOS)
    return QLatin1String("ios");
#elif defined(Q_OS_MAC)
    return QLatin1String("osx");
#elif defined(Q_OS_WINCE)
    return QLatin1String("wince");
#elif defined(Q_OS_WIN)
    return QLatin1String("windows");
#elif defined(Q_OS_LINUX)
    return QLatin1String("linux");
#elif defined(Q_OS_UNIX)
    return QLatin1String("unix");
#else
    return QLatin1String("unknown");
#endif
}

It depends on the used compiler.

For example, Windows' definition can be WIN32 or _WIN32.

And Linux' definition can be UNIX or __unix__ or LINUX or __linux__.

You can do:

#if MACRO0
    //code...
#elif MACRO1
    //code...
#endif

…where the identifier can be:

    __linux__       Defined on Linux
    __sun           Defined on Solaris
    __FreeBSD__     Defined on FreeBSD
    __NetBSD__      Defined on NetBSD
    __OpenBSD__     Defined on OpenBSD
    __APPLE__       Defined on Mac OS X
    __hpux          Defined on HP-UX
    __osf__         Defined on Tru64 UNIX (formerly DEC OSF1)
    __sgi           Defined on Irix
    _AIX            Defined on AIX
    _WIN32          Defined on Windows

use:

#ifdef __linux__ 
    //linux code goes here
#elif _WIN32
    // windows code goes here
#else

#endif