Re: singleton initialization

From:

Isaac Rodriguez <isaac.rodriguez@comcast.net>

Newsgroups:

comp.lang.c++.moderated

Date:

Tue, 15 May 2007 22:23:28 CST

Message-ID:

<1179278997.562940.307790@e65g2000hsc.googlegroups.com>

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

If you are returning a reference, why don't you implement it the
following way?

// In CTestClass.cpp

CTestClass& CTestClass::instance()
{
    static CTestClass theInstance;
    return theInstance;
}

BTW, implement instance in the .cpp file not in the class declaration.
I know for experience that VC++ 7.1 will inline some times the call to
instance() and there will be more than one object created, which is
not what you want from a singleton.

Back then when I found the problem, I asked this newsgroup about if it
was a bug in VC++ 7.1, but I didn't get any definitive answers, so
there might be other compilers with the same behavior.

Thanks,

- Isaac.

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