C++ 访问静态变量时未解析的外部符号
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unresolved external symbol when accessing a static variable
提问by Ken Li
class CommandManager {
public:
void sendText(std::string command);
static bool CommandManager::started;
private:
bool parseCommand(std::string commands);
void changeSpeed(std::vector<std::string> vec);
void help(std::vector<std::string> vec);
};
And here's the client code:
这是客户端代码：
CommandManager::started = true;
Linking these two files together I get:
将这两个文件链接在一起我得到：
1>UAlbertaBotModule.obj : error LNK2001: unresolved external symbol "public: static bool CommandManager::started" (?started@CommandManager@@2_NA)
1>C:\Development\School\cmput350-uofabot\UAlbertaBot\vs2008\Release\UAlbertaBot.dll : fatal error LNK1120: 1 unresolved externals
1> UAlbertaBotModule.obj : 错误 LNK2001: 未解析的外部符号 "public: static bool CommandManager::started" (?started@CommandManager@@2_NA)
1>C:\Development\School\cmput350-uofabot\UAlbertaBot\vs2008\Release\UAlbertaBot.dll：致命错误LNK1120：1个未解析的外部
Where did I go wrong here?
我这里哪里出错了？
回答by Nawaz
You're doing that incorrectly.
你这样做是错误的。
class CommandManager {
public:
void sendText(std::string command);
static bool started; //NOT this -> bool CommandManager::started
//...
};
then put the definition of static member in .cppfile as:
然后将静态成员的定义放在.cpp文件中：
#include "CommandManager.h" //or whatever it is
bool CommandManager::started = true; //you must do this in .cpp file
Now you can useCommandManager::startedin your client code.
现在，您可以使用CommandManager::started在客户端的代码。
回答by Basile Starynkevitch
You should have inside your class:
你应该在你的班级里有：
class CommandManager {
public:
void sendText(std::string command);
static bool started;
//// etc
};
and outside your class, in a *.ccfile (not in a *.hhheader file), a definition like
在你的班级之外，在一个*.cc文件中（而不是在*.hh头文件中），一个像
bool CommandManager::started;
BTW, I believe you'll better make that private.
顺便说一句，我相信你会更好地做到这一点private。
回答by Michael Krelin - hacker
Consider putting
考虑放
bool CommandManager::started;
where you defineother members.
在这里你定义的其他成员。
