问题描述
今天写项目时（在与elastisearch服务端的交互模块），遇到一个裸指针和智能指针指向同一块空间，导致段错误Segmentation fault，特此记录。
//error code
#include "es.hh"int main()
{// 创建es客户端，与es建立连接try{elasticlient::Client* client = new elasticlient::Client({"http://localhost:9200/"});// 创建索引EsIndex es_index(client, "user", "_doc");es_index.append("nickname", "text", "ik_maxword", true);es_index.append("user_id", "keyword", "standard");es_index.append("phone", "keyword", "standard");es_index.append("description", "text", "standard", false);es_index.append("avatar_id", "keyword", "standard", false);es_index.create();// 插入文档数据EsUpdate ud1(client, "user", "_doc", 1);ud1.addProperty("user_id", "USER4b862aaa-2df8654a-7eb4bb65-11111111");ud1.addProperty("nickname", "昵称 1");ud1.addProperty("phone", "手机号 1");ud1.addProperty("description", "签名 1");ud1.addProperty("avatar_id", "头像 1");ud1.submit();EsUpdate ud2(client, "user", "_doc", 2);ud2.addProperty("user_id", "USER14eeeaa5-442771b9-0262e455-e4663d1d");ud2.addProperty("nickname", "昵称 2");ud2.addProperty("phone", "手机号 2");ud2.addProperty("description", "签名 2");ud2.addProperty("avatar_id", "头像 2");ud2.submit();}catch (std::exception &e){std::cout << e.what() << std::endl;}return 0;
}
其中，EsIndex和EsUpdate对象都以智能指针shared_ptr保存一份es客户端的副本，用于与es服务端交互。
class EsIndex
{
public://....
private:std::shared_ptr<elasticlient::Client> _client;//...
};class EsUpdate
{
public://....
private:std::shared_ptr<elasticlient::Client> _client;//...
};
刚开始以裸指针传入EsIndex和EsUpdate，用于其内部创建智能指针。程序运行后报段错误，使用gdb调试后，提示异常信息如下：
错误原因
出了try作用域后，三个拥有智能指针的对象销毁，智能指针释放，计数器减到0，空间释放，此时elasticlient::Client对象被销毁了。
根据gdb报错信息，可能是程序结束前，client要结束与es服务端的对话Session，但是此时无法找到client了，所以报了段错误。
改正
不要混用裸指针和智能指针来指向同一块内存。 如果你决定使用智能指针来管理内存，就应完全依赖它，而避免在代码中保留指向同一内存的裸指针。
#include "es.hh"int main()
{// 创建es客户端，与es建立连接try{// elasticlient::Client* client = new elasticlient::Client({"http://localhost:9200/"});auto client = std::make_shared<elasticlient::Client>(std::initializer_list<std::string>{"http://localhost:9200/"});// 创建索引EsIndex es_index(client, "user", "_doc");es_index.append("nickname", "text", "ik_maxword", true);es_index.append("user_id", "keyword", "standard");es_index.append("phone", "keyword", "standard");es_index.append("description", "text", "standard", false);es_index.append("avatar_id", "keyword", "standard", false);es_index.create();// 插入文档数据EsUpdate ud1(client, "user", "_doc", 1);ud1.addProperty("user_id", "USER4b862aaa-2df8654a-7eb4bb65-11111111");ud1.addProperty("nickname", "昵称 1");ud1.addProperty("phone", "手机号 1");ud1.addProperty("description", "签名 1");ud1.addProperty("avatar_id", "头像 1");ud1.submit();EsUpdate ud2(client, "user", "_doc", 2);ud2.addProperty("user_id", "USER14eeeaa5-442771b9-0262e455-e4663d1d");ud2.addProperty("nickname", "昵称 2");ud2.addProperty("phone", "手机号 2");ud2.addProperty("description", "签名 2");ud2.addProperty("avatar_id", "头像 2");ud2.submit();// 搜索内容// std::string search_body = R"({// "query": {// "match_all": {}// }// })";// cpr::Response response = client.search("user", "_doc", search_body);// std::cout << "状态码： " << response.status_code << std::endl;// std::cout << "查找内容：" << response.text << std::endl;}catch (std::exception &e){std::cout << e.what() << std::endl;}return 0;
}
