c++设计问题尝试捕捉

发布于 2024-10-19 09:26:58 字数 536 浏览 2 评论 0原文

我有以下代码，其中 dbh 构造函数可能会抛出异常。我的问题是，dbh 是在 try 块内声明的。捕获后可以使用吗？如果是，是否存在范围解析与 {} 不同的其他异常？如果不是，最好的设计方案是什么？

status func(const char* field, char** value)
{
    try {
        dbhandler<recType> dbh(("dbName"),("table"));
    }
    catch (std::runtime_error &e) {
        LOG_ERR << e.what() << endl ;
        return false;
    }
    catch (...) {
        LOG_ERR << "Unknown exception" << endl ;
        return false;
    }

    rc = dbh.start("key",field, val);
    return rc;
}

原文

I have the following code in which dbh constructor may throw exception. The question I have is, dbh is declared inside try block. Will it be available after the catch? If yes, are there any other exceptions where the scope resolution is different than {} ? If not, what is the best design alternative?

status func(const char* field, char** value)
{
    try {
        dbhandler<recType> dbh(("dbName"),("table"));
    }
    catch (std::runtime_error &e) {
        LOG_ERR << e.what() << endl ;
        return false;
    }
    catch (...) {
        LOG_ERR << "Unknown exception" << endl ;
        return false;
    }

    rc = dbh.start("key",field, val);
    return rc;
}

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

樱娆 2024-10-26 09:26:58

捕获后可以使用吗？

不会。它会在声明它的块末尾被销毁，就像任何其他局部变量一样。

try {
    dbhandler<recType> dbh(("dbName"),("table")); 
}   // dbh.~dbhandler<recType>() is called to destroy dbh

最好的设计方案是什么？

在 try 块之外声明 dbh 或将使用它的所有代码移至 try 块中。哪一种最有意义取决于您的具体用例。

在某种程度上相关的说明中，如果您catch (...)，您应该重新抛出异常或终止应用程序：您不知道正在处理什么异常，并且通常您不知道是否继续执行是安全的。

Will it be available after the catch?

No. It will be destroyed at the end of the block in which it is declared, just like any other local variable.

try {
    dbhandler<recType> dbh(("dbName"),("table")); 
}   // dbh.~dbhandler<recType>() is called to destroy dbh

What is the best design alternative?

Declare dbh outside of the try block or move all the code that uses it into the try block. Which one makes the most sense depends on your specific use case.

On a somewhat related note, if you catch (...), you should either rethrow the exception or terminate the application: you have no idea what exception is being handled and in general you have no idea whether it is safe to continue executing.

回复收藏 0 原文

嗫嚅 2024-10-26 09:26:58

根据你的函数代码，这样写很有意义：

status func(const char* field, char** value)
{
    try {
        dbhandler<recType> dbh(("dbName"),("table"));
        status rc = dbh.start("key",field, val);
        return rc;
    }
    catch (std::runtime_error &e) {
        LOG_ERR << e.what() << endl ;
        return false;
    }
    catch (...) {
        LOG_ERR << "Unknown exception" << endl ;
        return false;
    }
}

According to your function code, it makes much sense to write it like that:

status func(const char* field, char** value)
{
    try {
        dbhandler<recType> dbh(("dbName"),("table"));
        status rc = dbh.start("key",field, val);
        return rc;
    }
    catch (std::runtime_error &e) {
        LOG_ERR << e.what() << endl ;
        return false;
    }
    catch (...) {
        LOG_ERR << "Unknown exception" << endl ;
        return false;
    }
}

回复收藏 0 原文

~没有更多了~