Hi Tim,

On Mon, Feb 23, 2009 at 7:01 PM, <timbla...@gmail.com> wrote:

> In my application, I have a need to track characteristics of message
> fields on a field-by-field basis, e.g. has this field changed. This is
> very much like what is already done in libprotobuf code for tracking
> whether a field has been set yet. Looking under the hood, I found the
> _has_bits_, a simple bitfield tracking mechanism, and thought I could
> reuse this for tracking other characteristics my app is interested in.
> So far, though, it looks like the bit numbers are hard-coded in the
> _set_bit/_clear_bit/has_bit method calls. Is there any plan to modify
> the compiler to define these field bits as constants or at least
> #defines in the generated c++ header file?

_has_bits_ is an internal (private) implementation detail.  We don't plan to
make it publicly-accessible.

Aside from this general question, is there another simple way you can
> think of to track what fields have changed? I couldn't find anything
> in the API that allowed diff'ing two instances of the same message
> class. (I also couldn't find any equality operators, so had to define
> that myself; please advise if this was unnecessary.)

It's not included in the base library, but you could write code to do this
based on reflection.

> Thanks,
> Tim
> >

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