[Warning] catching polymorphic type 'class std::out_of_range' by value [-Wcatch-value=]

这是一个编译器的警告，意思是你在异常处理中捕捉了一个多态类型（即使用了继承关系的类），但是你使用了值传递方式，可能会导致切片问题。

解决这个警告的方法是使用引用或指针来传递异常对象，例如：

try {
  // some code that may throw std::out_of_range
} catch(std::out_of_range& e) {
  // handle the exception
}

或者

try {
  // some code that may throw std::out_of_range
} catch(std::out_of_range* e) {
  // handle the exception
}

这样可以避免出现切片问题。

相关问题

terminating with uncaught exception of type std::exception: std::excepti

on: std::exception: std::exception is a base class for all standard exceptions in C++. It is typically used to catch any exception that is derived from it. When the program terminates with an uncaught exception of type std::exception, it means that an exception occurred during the execution of the program, but there was no catch block to handle it.

To resolve this issue, you can add a try-catch block around the code that potentially throws the exception. Here's an example:

try {
    // Code that may throw an exception
} catch (const std::exception& e) {
    // Handle the exception
}

By catching the exception, you can handle it gracefully and prevent the program from terminating abruptly. Make sure to replace the comment with the actual code that may throw the exception.

If you provide more specific details about your code or the exception you are encountering, I might be able to provide more targeted assistance.

2059-Authentication pludin 'catching_sha2_password" cannot be loaded

这个问题通常是由于 MySQL 版本升级或者更换 MySQL 安装包导致的，因为新版 MySQL 默认使用了 "caching_sha2_password" 来进行身份验证，而旧版 MySQL 使用的是 "mysql_native_password"。解决方案如下：

1. 升级 MySQL 客户端库或者安装包到最新版本，或者安装 MySQL 5.7 版本及以下版本的。

2. 修改 MySQL 用户的身份验证方式，将其改为 "mysql_native_password"。可以通过以下 SQL 语句来修改：

ALTER USER 'username'@'localhost' IDENTIFIED WITH mysql_native_password BY 'password';

其中，'username' 和 'password' 分别为你的 MySQL 用户名和密码。

3. 修改 MySQL 配置文件，在 [mysqld] 部分添加以下内容：

default-authentication-plugin=mysql_native_password

修改完成后，重启 MySQL 服务即可。