Re: memory trampling

From:
James Kanze <james.kanze@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Tue, 21 Oct 2008 15:10:23 -0700 (PDT)
Message-ID:
<3d30c6c7-6fde-4bd8-b45a-9fe55f2ec2c1@l76g2000hse.googlegroups.com>
On Oct 21, 5:31 pm, Zeppe
<ze...@remove.all.this.long.comment.yahoo.it> wrote:

joshuajnoble wrote:

I threw together a quick test here, I'm thinking my problem
is in what I'm doing with the static pointer (perhaps).
Here's my Singleton:


I'm not sure, I can't see major problems in this piece of code.


    [...]

   val2 = "abcdefghijklmn";


this is maybe val2[0] = "..."; otherwise, it won't compile.


I'd count that as a major problem, since it means that he's not
posting the actual code which causes the problem.

However, it will give you warning anyway regarding the
conversion from const char* (the string literal) to char*.


The standard doesn't require warnings:-). As a quality of
implementation issue, of course, a good compiler should give the
warning. Provided you've invoked it as a good C++
compiler---every compiler I know needs a half a dozen options to
be truly a C++ compiler.

    [...]

Surely inst is initialised somewhere to NULL, as in

SingletonImpl* SingletonImpl::inst = NULL;

or similar. Otherwise it won't link.


You don't actually need the initialization, since objects with
static lifetime are zero initialized anyway. But without the
definition, it's undefined behavior---with the compilers I
usually use, it won't link either, but the standard doesn't
require an error of any sort, and it's quite possible that a
compiler could implicitly supply the definition, but skip the
zero initialization for it. That would still be conforming (but
not really what I would call a very good implementation).

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