Re: Protecting against uninitialized variables

From:
"Tim Conkling" <tconkling@gmail.com>
Newsgroups:
comp.lang.c++.moderated
Date:
Tue, 20 Mar 2007 01:48:55 CST
Message-ID:
<1174357591.375732.212570@l77g2000hsb.googlegroups.com>
On Mar 19, 3:22 pm, Greg Herlihy <gre...@pacbell.net> wrote:

In my view this solution is over-engineered - it goes far beyond what is
required to ensure the zero-initialization of a fundamental type serving as
a class member. I would think that a more pared-down implementation would do
the job:

     template <class T>
     struct safe_type
     {
         safe_type() : value(T()) {}

         operator T&() { return value; }
     private:
         T value;
     };

     typedef safe_type<int> safe_int;

     struct C
     {
         C() {}
     private:
         safe_int i;
     };


Thanks, Greg. I wasn't aware that it was possible to default-
initialize the fundamental types. How does this look as a revised
implementation?

template <class T>
struct safe_type
{
        safe_type() : m_val(T()) {}
        safe_type(T val) : m_val(val) {}

        T& operator=(T val) { m_val = val; return *this; }

        operator T&() { return m_val; }
        operator const T&() const { return m_val; }

        T operator->() const { return m_val; }

private:
        T m_val;
};

The operator->() overload is there to allow declarations like this:

safe_type<Foo*> m_foo;

To be used in place of

Foo* m_foo;

Tim

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