Messages in this thread | | | Subject | Re: [PATCH] Use NULL instead of integer 0 in security/selinux/ | From | Michael Poole <> | Date | Thu, 08 Jul 2004 11:00:02 -0400 |
| |
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 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |