Re: [Bug-tar] invalid archive provokes segfault

[Helmut Waitzmann]

Jim Meyering <address@hidden> writes:

>BTW, using `*p' and `p' as arguments to strtoul is odd.
>Doesn't that rely on undefined behavior?  Sort of like
>using memcpy with overlapping regions?

I don't think so.  In order to call strtoul (*p, p, 10),
the run-time environment evaluates the values *p, p, and 10 in an
unspecified order.

However, this evaluation has completed before strtoul gets called:  All
parameters in the programming language C are call by value parameters.
(Even array parameters are call by value parameters:  The address of the
first element of the array is supplied as a pointer value.  In no
circumstances there are lvalue parameters.)

So,

   strtoul(*p, p, 10);

is equivalent to

   { char * tmp = *p;
     strtoul(tmp, p, 10));
   }

with respect to the evaluation of the parameters.  Or do I miss
something?  Maybe, I'm missunderstanding you?
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