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From: Peter Dimov (pdimov_at_[hidden])
Date: 2005-05-09 05:02:28

Beman Dawes wrote:
> "Peter Dimov" <pdimov_at_[hidden]> wrote in message
> news:00a201c55418$585bb2c0$6401a8c0_at_pdimov2...
>> When a socket is thrown your way, you just run it by the list and
>> conclude that no bit needs to be set.
> But that is about the same as having an other_flag, except that the
> name is 0 instead of other_flag.

You don't need a name because the user will never test for this category.

if( status() & other_flag )
    // OK, so what do I do here?

The other categories have expectations attached, so testing for them makes

> Giving it a name makes it more obvious that a return from status()
> may not have any of the other bits set.

I, as a user, wouldn't rely on the "one bit rule" anyway. Idiomatic code
should work with any result from status(), as long as it makes sense. It is
reasonable to expect a future status() to return readable_flag and
writable_flag in addition to exists_flag (currently named !not_found_flag to
preserve the one bit rule.)

As others have pointed out, a bitmask type is not used if one and only one
bit will be set. :-)

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