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    SubjectRe: [PATCH] Use NULL instead of integer 0 in security/selinux/
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    Richard B. Johnson writes:

    > On Thu, 8 Jul 2004, P. Benie wrote:
    >
    >> False. "An integer constant expressions with the value 0, or such an
    >> expression cast to type void *, is called a null pointer constant. If a
    >> null pointer constant is assigned to or compared for equality with a
    >> pointer, the constant is converted to a pointer of that type", and "Any
    >> two null pointers shall compare equal."
    >>
    >> In other words, when you use 0 as a null pointer, you really do get a null
    >> pointer. If you are working on an architecture where the bit pattern of
    >> the integer 0 and null pointers are not the same, the compiler will
    >> perform the appropriate conversion for you, so it is always correct to
    >> define NULL as (void *)0.
    >
    > That's NOT what is says. It states that a NULL pointer is converted to
    > the appropriate type before any comparison is made. It does NOT say
    > that 0 is a valid null-pointer.

    Could you please elaborate the rules of English in which "An integer
    constant expresion with the value 0 [...] is called a null pointer
    constant" does not mean that 0 is a null pointer? 0 is certainly an
    integer constant expression with the value 0, so there must be
    something extraordinarily subtle in the second half of the sentence.

    Michael
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