现在,我得到一个“未定义的引用错误消息 'GlobalClass :: s_instance' 和“GlobalClass ::实例()”,分别对这些语句:
GlobalClass *GlobalClass::s_instance = 0;
GlobalClass::instance()->set_value(myAddress); \\ <== undefined reference
std::cout << "====>address is is " << GlobalClass::instance()->get_value()
任何想法的代码如下所示:
================================================
#ifndef GLOBALCLASS_H_
#define GLOBALCLASS_H_
#include <string>
class GlobalClass {
public:
std::string get_value();
void set_value(std::string);
static GlobalClass *instance();
static GlobalClass *s_instance;
private:
std::string m_value;
};
#endif /* GLOBALCLASS_H_ */
=========================================== ====
#include <string>
#include "GlobalClass.h"
/*
GlobalClass(int v = 0)
{
m_value = v;
}
*/
static GlobalClass *s_instance;
std::string GlobalClass::get_value()
{
return m_value;
}
void GlobalClass::set_value(std::string v)
{
m_value = v;
}
static GlobalClass *instance() {
if (!s_instance)
s_instance = new GlobalClass;
return s_instance;
}
======================================= ====================
#include <iostream>
#include "GlobalClass.h"
using namespace std;
int main() {
GlobalClass::s_instance = 0; \\ <== undefined reference
std::string myAddress = "abc";
GlobalClass::instance()->set_value(myAddress); \\ <== undefined reference
std::cout << "====>address is is " << GlobalClass::instance()->get_value()
\\ <== undefined reference
<< std::endl;
return 0;
}
确切的重复:http://stackoverflow.com/questions/1122938/undefined-reference-c-linker-error – 2009-07-14 01:31:34
我知道这是一个不同的错误,但它是同样的问题,因为你的其他问题,所以我在那里张贴答案并投票结束这一问题。 – 2009-07-14 01:37:32