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    SubjectRe: [PATCH] Remove pointless <0 comparison for unsigned variable in fs/fcntl.c
    On Tue, 23 Nov 2004, Timur Tabi wrote:

    > Linus Torvalds wrote:
    > > which might warn on an architecture where "pid_t" is just sixteen bits wide.
    > > Does that make the code wrong? Hell no.
    > Wouldn't something like "sizeof(pid_t) > 2" be a better test? It certainly
    > would be a lot easier to understand than comparing with 0xffff.
    That was not the point of the example Linus gave.
    The example Linus gave was a function taking a pid_t argument and then
    comparing the value of the argument passed against 0xffff - the /value/ of
    the pid_t argument passed, not the size of the datatype.

    int fn(pid_t a)
    if (a > 0xffff)

    if pid_t is 16 bit, then the value can never be greater than 0xffff but,
    if pid_t is greater than 16 bit, say 32 bit, then the argument "a" could
    very well contain a value greater than 0xffff and then the comparison
    makes perfect sense. So, while you'd get a warning on architectures where
    pid_t is 16bit or less you won't get a warning when pid_t is greater than
    16 bit. "fixing" that warning would clearly be wrong, no argument about

    Jesper Juhl

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