Re: shared_ptr doesn't use unsigned reference count?

From: James Curran/MVP (jamescurran_at_[hidden])
Date: 2001-10-24 13:54:10

        I'm not sure I buy that in this case.  Shared_ptr has an edge
condition at zero by its very nature.  Doing something at count =
0xFFFFFFFF that should have been done at count = 0x00000000 is just
wrong, and considering 0xFFFFFFF a small negative number rather than a
large positive number doesn't make it any more or less wrong.

        So, by making the count unsigned, we would be formalizing the
precondition that is already there.

    Truth, 
     James Curran

-----Original Message-----

        Message: 3
           Date: Tue, 23 Oct 2001 22:20:54 -0700
           From: Darin Adler <darin_at_[hidden]>
        Subject: Re: shared_ptr doesn't use unsigned reference count?

        That leaves us with reason 3, clarity.

        Many C and C++ programmers prefer to avoid the pitfalls of
unsigned
        arithmetic -- having the edge of the numeric range right next to
0 	makes it easier to write incorrect code. These programmers don't
consider clarity reason enough to use an unsigned type, and only use
an unsigned integer type when either reason 1 or 2 applies.

        Let me turn your question around.

        Can anyone tell me a practical advantage that would result from
making
        shared_ptr's pn member be unsigned?