C++ 对静态变量的未定义引用
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Undefined reference to static variable
提问by Сергей Подковырин
Possible Duplicate:
C++: undefined reference to static class member
可能的重复：
C++：对静态类成员的未定义引用
I'm using MinGW. Why static variable is not working
我正在使用 MinGW。为什么静态变量不起作用
[Linker error] undefined reference to `A::i'
#include <windows.h>
class A {
public:
static int i;
static int init(){
i = 1;
}
};
int WINAPI WinMain (HINSTANCE hThisInstance,
HINSTANCE hPrevInstance,
LPSTR lpszArgument,
int nFunsterStil){
A::i = 0;
A::init();
return 0;
}
回答by billz
You only declared A::i, need to define A::ibefore using it.
您只声明了A::i，需要A::i在使用前定义。
class A
{
public:
static int i;
static void init(){
i = 1;
}
};
int A::i = 0;
int WINAPI WinMain (HINSTANCE hThisInstance,
HINSTANCE hPrevInstance,
LPSTR lpszArgument,
int nFunsterStil)
{
A::i = 0;
A::init();
return 0;
}
Also your init() function should return a value or set to void.
此外，您的 init() 函数应该返回一个值或设置为 void。
回答by Olaf Dietsche
You have declared A::iinside your class, but you haven't defined it. You must add a definition after class A
您已A::i在类中声明，但尚未定义它。您必须在之后添加定义class A
class A {
public:
static int i;
...
};
int A::i;
