Messages in this thread | | | Date | Fri, 30 May 2003 16:43:02 +0200 | From | Andries Brouwer <> | Subject | Re: buffer_head.b_bsize type |
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On Fri, May 30, 2003 at 04:24:34PM +0200, Andries Brouwer wrote: > On Thu, May 29, 2003 at 04:28:41AM -0700, William Lee Irwin III wrote: > > > The thought behind my comment was that it didn't make sense to allow > > the representation to go negative. There of course shouldn't ever be > > any need to allow >= 2GB b_size to be representable. > > Not about this particular case, but as a general remark: > Use of unsigned is dangerous - use of int is far preferable, > everywhere that is possible. > > With ints the test a+b > c is equivalent to the test a > c-b.
[of course I meant: With smallish ints, so that no overflow occurs]
> As soon as there is some unsigned in an expression comparisons > get counterintuitive because -1 is very large. > Thus, 1+sizeof(int) > 3 is true, but 1 > 3-sizeof(int) is false. > > It has happened several times that kernel code was broken because > some variable (that always was nonnegative) was made unsigned. > > Andries
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