Re: Non-static singleton setup to control life time
Kris Prad wrote:
I want to setup a singleton, without 'static' initialization. My
motive is to control the life time of the Singleton, bounded by its
scope, something I cannot do with the statics.
Not this way. This uses static:
Single* Get()
{
Static Single s; // do not want static
Return &s;
}
Instead, I am doing this (please ignore thread safety issues)
Single* g_Single = NULL; // global singleton ptr
struct Single
{
Single()
{
if (!g_Single)
{
g_Single = this;
}
else
{
throw string("Single is a singleton");
}
}
~Single()
{
g_Single = NULL;
}
};
Is this ugly or acceptable?
Kris
What is wrong with this:
class Single {
public:
Single(){
if(exists) throw("You can only have one object of type Single");
exists = true;
// do rest
}
~Single() { exists = false }
// rest of interface
private:
static bool exists;
// rest of private interface etc.
};
bool Single::exists(false);
The trouble with your use of a global variable is that it could be
accidentally modified and the compiler will not be able to help you.
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