cpp terminology

platform

https://stackoverflow.com/questions/6649936/c-compiling-on-windows-and-linux-ifdef-switch

    __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