Re: singleton initialization

Fei Liu <>
Tue, 15 May 2007 17:02:08 CST
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;

This doesn't make sense. How can the compiler create this object at
compile time? Change this to:
static CTestClass& instance()
    static CTestClass* m_instance;
    if(!m_instance) m_instance = new CTestClass;
    return m_instance;

        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()

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