Re: singleton

From:
Ian Collins <ian-news@hotmail.com>
Newsgroups:
comp.lang.c++
Date:
Tue, 25 Mar 2008 22:06:17 +1300
Message-ID:
<64rtk9F2cjptfU20@mid.individual.net>
Rahul wrote:

On Mar 25, 12:49 pm, Ian Collins <ian-n...@hotmail.com> wrote:

Rahul wrote:

On Mar 25, 7:17 am, thomas <FreshTho...@gmail.com> wrote:

hi guys,
-----code-----
class A{
private:
    A(){}
public:
    static A *getInstance(){
       static A *a = new A(); //-------L1----
       return a;
    }};
-----code-----
I use the static keyword to declare a static instance A,
I wonder if getInstance() is called multiple times, will L1 be
executed multiple times?
generally a initialization sentence of static variable will be
executed only once, but I'm not sure what will the c++ compiler expand
for L1.

make sure its thread safe too... you could consider using a mutex or
binary semaphore for the same...

For the same what? The implementation should guarantee the static
variable is initialised once only.


*Please* don't quote signatures.

for thread safety...


The object should manage its own thread safety, not the singleton.

--
Ian Collins.

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