Re: Singleton_pattern and Thread Safety

Leigh Johnston <>
Fri, 10 Dec 2010 16:42:19 +0000
On 10/12/2010 15:56, Leigh Johnston wrote:

On 10/12/2010 15:29, James Kanze wrote:

On Dec 10, 1:16 pm, Leigh Johnston<> wrote:

On 10/12/2010 09:52, James Kanze wrote:

On Dec 9, 5:05 pm, Marcel M ller<> wrote:

Pallav singh wrote:


Note that the above still risks order of destruction issues;
it's more common to not destruct the singleton ever, with
something like:

namespace {

Singleton* ourInstance =&Singleton::instance();

if (ourInstance == NULL)
ourInstance = new Singleton;
return *ourInstance;

(This solves both problems at once: initializing the variable
with a call to Singleton::instance and ensuring that the
singleton is never destructed.)

James "Cowboy" Kanze's OO designs includes objects that are never
destructed but leak instead?

And where do you see a leak?

Is that a serious question?

The only real difference between the two programs below is the amount of
memory leaked:

int main()
int* p = new int;

int main()
int* p = new int;
p = new int;

A singular memory leak (one that is not repeated so doesn't consume more
and more memory as a program runs) is still a memory leak.

I will ignore the predictable, trollish part of your reply.


Furthermore if you placed your singleton code into a DLL and the DLL was
continuously loaded and unloaded I think you would see plain evidence
that this is in fact a memory leak.


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