在C ++中调度异常 [英] Dispatching exceptions in C++

问题描述

如何调度异常，以便以集中，用户友好的方式处理错误处理和诊断？

How should exceptions be dispatched so that error handling and diagnostics can be handled in a centralized, user-friendly manner?

例如：

• DataHW类处理与某些数据采集硬件的通信。


• DataHW类可能会基于一些可能的错误：间歇信号，无信号，CRC故障，驱动器错误。


• DataHW类由许多不同的代码块调用，这些代码具有不同的获取和分析类型。

正确的错误处理策略取决于异常的类型和尝试的操作。 （在间歇信号，重试X次然后告诉用户;在驱动程序错误，记录错误和重新启动驱动程序等）。应如何调用此错误处理策略？

The proper error handling strategy depends on the type of exception and the operation being attempted. (On intermittent signal, retry X times then tell the user; on a driver error, log an error and restart the driver; etc.) How should this error handling strategy be invoked?

• 将错误恢复到每个异常类中：这将导致异常类非常大，并包含高级UI和系统管理代码。


• 为每种类型的异常提供单独的 catch 块：因为DataHW类是从许多不同的地方调用的，每个 catch 块将必须在每个调用站点重复。 c> 函数与一个基于RTTI的开关语句：RTTI和 switch 通常表示未能应用OO设计，似乎是最不好的替代方案。

• Coding error recovery into each exception class: This would result in exception classes that are rather large and contain high-level UI and system management code. This seems bad.
• Providing a separate catch block for each type of exception: Since the DataHW class is called from many different places, each catch block would have to be duplicated at each call site. This seems bad.
• Using a single catch block that calls some ExceptionDispatch function with a giant RTTI-based switch statement: RTTI and switch usually indicates a failure to apply OO design, but this seems the least bad alternative.

推荐答案

避免在每个调用站点重复catch块（...）并调用重新抛出和分派的共享处理函数：

Avoid duplicating the catch blocks at each call site by catching (...) and calling a shared handler function which rethrows and dispatches:

f()
{
    try
    {
        // something
    }
    catch (...)
    {
        handle();
    }
}

void handle()
{
    try
    {
        throw;
    }
    catch (const Foo& e)
    {
        // handle Foo
    }
    catch (const Bar& e)
    {
        // handle Bar
    }
    // etc
}

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