Re: singleton initialization

John Moeller <>
Tue, 15 May 2007 22:23:54 CST
Salt_Peter wrote:

On May 15, 4:00 pm, Eric <> wrote:

I created a singleton class as in the example below. The application
sporadically crashes in the second line of the main function as shown.
However, when I change the singleton such that the static pointer is a
class member (defined in the cpp file) and the instance function
creates the object if the pointer is NULL, then it works fine. I would
appreciate any explanations as to why this happens.

class CTestClass
    static CTestClass& instance()
        static CTestClass* m_instance = new CTestClass;
        return *m_instance;
    CTestClass() { /* do some stuff */ }


int main()
    CTestClass::instance(); // initialize singleton here to
avoid future race conditions
    // sporadically crashes here when using CTestClass::instance()


By 'race conditions', did you think that some local persistant
variable is immune to thread locks because its static?

It's immune to race conditions because he hasn't started any other
threads yet (assuming that he doesn't try to start any threads from
static initializers).


John Moeller

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