Re: Threadsafe singletons
fluidparody@yahoo.com wrote:
Tell me if I have your idea correct because this isn't working for me.
/////////// singleton.h
class Singleton
{
char *name;
public:
static Singleton& GetInstance();
char *GetName() const { return name; }
void SetName(char *n) { name = n; }
private:
Singleton();
};
/////////// singleton.cpp
#include "singleton.h"
Singleton::Singleton()
{
}
/////////// main.cpp
#include "singleton.h"
#include <iostream>
Singleton& Singleton::GetInstance()
{
static Singleton s;
return s;
}
static struct InitSingleton
{
InitSingleton()
{
Singleton s = Singleton::GetInstance();
s.SetName("Super Duper");
}
} s_init;
int main()
{
Singleton singleton = Singleton::GetInstance();
std::cout << "The singleton's name is: " <<
singleton.GetName() << std::endl;
return 0;
}
I'm not getting a "Super Duper" Singleton
Did it crash? Your constructor doesn't initialise the 'name' member
and the statement s.SetName("Super Duper") is setting the name of a
copy of the class (not the original).
Rather than
Singleton s = Singleton::GetInstance();
you should instead write
Singleton& s = Singleton::GetInstance();
I suggest you make the copy constructor and assignment operator of your
Singleton class private to avoid copying.
BTW I also suggest you use a proper string member rather than simply
alias a null terminated string with a char pointer. It's rather
dangerous.
Cheers,
David Barrett-Lennard
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
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