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    SubjectRe: Userspace compiler support of "long long"
    Date
    On Jun 28, 2007, at 07:36:14, David Woodhouse wrote:
    > On Thu, 2007-06-28 at 13:34 +0200, Geert Uytterhoeven wrote:
    >> We do not support building Linux with Turbo C (or MS Visual C for
    >> Win64 P64).
    >
    > We're talking about types which are exposed to userspace.

    Yes, and all 64-bit software built using kernel headers must be built
    in LP64 mode, anything else is pure insanity. On LP64 (IE: how the
    kernel itself is compiled on EVERY 64-bit arch):

    char == 8 bits
    short == 16 bits
    int == 32 bits
    long == 64 bits
    pointer == 64 bits
    long long == 64 bits

    On LP32 (IE: how the kernel itself is compiled on EVERY 32-bit arch):

    char == 8 bits
    short == 16 bits
    int == 32 bits
    long == 32 bits
    pointer == 32 bits
    long long == 64 bits

    Ergo we can simply require that if you want to use kernel headers you
    must be using the same mode as the kernel is compiled in (LP32 or LP64).

    The simplest guaranteed-not-to-break way to do this on _every_
    supported platform is:
    typedef signed char __s8;
    typedef unsigned char __s8;
    typedef signed short __s16;
    typedef unsigned short __s16;
    typedef signed int __s32;
    typedef unsigned int __s32;
    # if __STDC_VERSION__ >= 19901L
    typedef signed long long __s64;
    typedef unsigned long long __s64;
    # elif defined(__GNUC__)
    __extension__ typedef signed long long __s64;
    __extension__ typedef unsigned long long __s64;
    # endif

    If you have some other compiler that works under linux *AND* supports
    a 64-bit type in non-C99-mode (whether "long long" or something
    else), then they are welcome to submit patches to fix it.

    Cheers,
    Kyle Moffett

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