Re: ARM compiler misbehaves ?

[Bill Gatliff <bgat at billgatliff dot com>]

Richard:


Richard wrote:

> > > Actually, I'm pretty sure it is guaranteed to work as long as the 
> > > compiler can see the "packed" attribute during compilation (if it 
> > > couldn't, that would be a serious structural problem in your source code!).
> >
> > Which claimed it should work.  It doesn't, and isn't intended to.

My claim was in response to the original poster's use of a _reference_ 
to the packed structure member, by name, as a parameter to printf().  
Not through a pointer.

Manipulations through pointers won't work, that much should be clear by 
now (as should be the underlying reason).  But _references_ to packed 
structure members by name, even when misaligned, do work.  Gcc will 
reconstruct the misaligned object in a properly-aligned one (a register, 
or on the stack), when necessary.



b.g.

--
Bill Gatliff
Affordable GNU and Linux training and consulting services.
bgat@billgatliff.com



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