编译 C++ 时体系结构x86_64的未定义符号

Undefined symbols for architecture x86_64 when compiling c++

本文关键字：未定义 符号 x86 C++ 体系结构 编译      更新时间：2023-10-16

我不断收到这个错误，这让我发疯了！

Undefined symbols for architecture x86_64:
  "SSResourcesDepot::_sharedInstance", referenced from:
    SSResourcesDepot::sharedInstance() in SSResourcesDepot.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

我的代码如下所示：

#ifndef SolarSystem_SSResourcesDepot_h
#define SolarSystem_SSResourcesDepot_h
#include "SSResource.h"
/* SSResourcesDepot is implemented as a Singleton Depot that keeps track of all
 * requested Resource objects, and avoid loading them twice in memory. */
class SSResourcesDepot {
    SSResourcesDepot() {};
    SSResourcesDepot(SSResourcesDepot const&){};
    SSResourcesDepot& operator=(SSResourcesDepot const&){};
    static SSResourcesDepot* _sharedInstance;
    SSResource* _search(std::string resourceName);
    SSResource* _load(std::string resourceName);
public:
    static SSResourcesDepot* sharedInstance();
    SSResource* requestResource(std::string resourceName);
};
#endif

和：

#include <iostream>
#include "SSResourcesDepot.h"

#pragma mark Public methods
SSResourcesDepot* SSResourcesDepot::sharedInstance() {
    if (SSResourcesDepot::_sharedInstance == 0) {
        SSResourcesDepot::_sharedInstance = new SSResourcesDepot();
    }
    return SSResourcesDepot::_sharedInstance;
}
SSResource* SSResourcesDepot::requestResource(std::string resourceName) {
    SSResource *resource = this->_search(resourceName);
    if (resource == NULL) resource = this->_load(resourceName);
    return resource;
}

#pragma mark Private methods
SSResource* SSResourcesDepot::_search(std::string resourceName) {
    return NULL;
}
SSResource* SSResourcesDepot::_load(std::string resourceName) {
    return NULL;
}

对我来说，它似乎完全有效，但是Apple-O-Matcher一直在抱怨，并且它不允许我编译... ：-S

提前感谢！

您没有初始化static成员。

加

SSResourcesDepot* SSResourcesDepot::_sharedInstance = NULL;

到您的实现文件。

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