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    SubjectRe: [GIT] Sparc
    On Tue, Aug 17, 2010 at 07:12:45PM -0700, David Miller wrote:
    > From: Linus Torvalds <torvalds@linux-foundation.org>
    > Date: Tue, 17 Aug 2010 18:31:50 -0700
    >
    > > Confused yet?
    >
    > Beyond...
    >
    > > The basic rule becomes: never _ever_ overflow 'int' in a constant,
    > > without specifying the exact type you want. That way you avoid all the
    > > subtle cases.
    >
    > That's easier to understand.

    Actually, it's not that complicated:

    1) base and suffices choose the possible types.
    2) order of types is always the same: int -> unsigned -> long -> unsigned
    long -> long long -> unsigned long long
    3) we always choose the first type the value would fit into
    4) L in suffix == "at least long"
    5) LL in suffix == "at least long long"
    6) U in suffix == "unsigned"
    7) without U in suffix, base 10 == "signed"

    That's it. C90 differs from C99 only in one thing - long long (and LL) isn't
    there. The subtle mess Linus has mentioned is C90 gccism: gcc has allowed
    unsigned long for decimal constants, as the last resort. I.e. if you had
    a plain decimal constant that wouldn't fit into long but would fit into
    unsigned long, gcc generated a warning and treated it as unsigned long.
    C90 would reject the damn thing. _Bad_ extension, since in C99 the same
    constant would be a legitimate signed long long.

    But yes, "use the suffix when unsure" is a damn good idea, _especially_ since
    the sizeof(long) actually varies between the targets we care about.


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