Re: question re. usage of "static" within static member functions of a class

James Kanze <>
Tue, 8 Sep 2009 14:26:22 -0700 (PDT)
On Sep 7, 7:24 am, "Chris M. Thomasson" <n...@spam.invalid> wrote:

"ssb" <> wrote in message

During a code review, I found the following lines of code:


The "instance" method was implemented as follows:
Data* Data::instance()
     static Data* model = new Data();
     return model;
I have never come across a situation where a pointer was set
to static in such a case. Is this valid?

It's a singleton.

And to answer the question, it's perfectly valid. A pointer is
an object, just like any other variable, and obeys the same
rules as other variables.

What are the potential pitfalls in such programming practices?

The storage that `model' points to will never be destroyed,
also it's not thread-safe.

Not being destroyed is presumably the reason the code is written
this way. Most of the time, you don't want a singleton to be
destructed. In other word, it's a feature designed to avoid
pitfalls. As for thread-safety, it depends on the
implementation, it is thread safe---modulo bugs---in g++. (But
you're probably right for most implementations.)

James Kanze

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