Re: bootstrap problem with union Lisp_Object

[Andreas Schwab]

Stefan Monnier <address@hidden> writes:

>>>> I'm still trying to track this down, but just for the record: If I
>>>> build recent sources with CC='gcc -DENABLE_CHECKING - 
>>>> DUSE_LISP_UNION_TYPE', bootstrapping fails:
>>> 
>>> Fixed...  With these options enabled, EQ evaluates its arguments  
>>> twice.
>
>> I think that should be fixed.  The requirement that arguments of EQ or
>> NILP need to be side effect free is too easy to forget, since it is
>> nowhere documented.
>
> The argument of *any* macro should be free of side effects.

Not necessarily.  Making macros safe on side effects is usually not hard,
and in the case of EQ it is trivial too:

#define EQ(x, y) ((x).i == (y).i)

Andreas.

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Andreas Schwab, SuSE Labs, address@hidden
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