[avr-chat] Re: AVR-chat Digest, Vol 18, Issue 5

[Steve Franks]

> > I have always ignored these:
> >
> > IPmcStream.h:32: warning: alignment of 'IPmcStream::_ZTV10IPmcStream'
> > is greater than maximum object file alignment.  Using 1
> >
> > In the past without problems.  One day, it's going to burn me, no
> > doubt.  Anyone know what this is trying to tell me?  I'm not playing
> > with any alignement or __packed__ attirbutes, fyi.
>
> I guess that member function is virtual? G++ always gives this warning for
> every virtual member function. It must have something to do with the vtable.
> Probably a bug in avr-g++. The warning should be harmless, since avr as an
> 8  bit architecture obviously doesn't have any alingment requirements.

That was my thinking too - virtual functions causing compiler
confusion.  I refactored one class a few months ago, just to clean it
up (still has virtuals), and it went away, but now I see it in a new
class.  These things make me uneasy.  The class was full of
pure-virtuals, that were all implemented in a derived class, and it
just wouldn't link to save my life.  I stubbed all the pure's into do
nothing functions, and it links fine, and calls the derived functions
correctly from a pointer to the base.  I double-and triple checked the
signatures, and they were identical.  I guess avr-g++ just doesn't
handle pure virtuals?  The alignment warning is still there, however.
I guess I'll just mask it out.  As you said, it appears harmless.

Steve