Re: Fortran's Equivalence

[kst@sd.aonix.com (Keith Thompson)]

In <dewar.860159911@merv> dewar@merv.cs.nyu.edu (Robert Dewar) writes:
> Keith said
> 
> <<1. If you're going to implement overlays using address clauses, it's safer
>    (and can't do any harm) to declare all the overlaid objects as aliased.
>    Pragma Volatile might be even better.  Perhaps someone more familiar
>    with this than I am can elaborate (or execute, or evaluate 8-)}).>>
> 
> There is no particular point in declaring these objects aliased, unless you
> intend to take their address or take a pointer to them.
[...]

To get the overlay in the first place, you have to take the address of
at least one of the objects (unless you use some other ugly trick):

    Obj1 : Some_Type;
    ...
    Obj2 : Some_Other_Type_With_Compatible_Size_And_Alignment;
    for Obj2'Address use Obj1'Address;

So at least Obj1 should be declared aliased, right?

-- 
Keith Thompson (The_Other_Keith) kst@sd.aonix.com <http://www.aonix.com> <*>
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