异常与错误代码vs.断言 [英] Exception vs. error-code vs. assert

问题描述

我正在使用一个可生成设备报告的库。 generate_report（const std :: string& no）成员函数可能会由于各种原因失败：

I'm working on a library that generates reports of devices. The generate_report (const std::string& no) member function can fail due to various reasons:

1. 无效报告号


2. 无效状态（ report_generator 是FSM）


3. 没有设备处于活动状态


4. 报告生成期间出现错误

1. invalid report no.
2. invalid state (the report_generator is a FSM)
3. no device is active
4. error during report generation

最好是这些错误？

• 只需返回 true 或 false


• 返回错误代码


• 断言并记录




• 上述任何组合

• just return true or false
• return error code
• assert and log
• throw exception(s)
• any combination of the above

某些上下文信息：正常工作流程如下。用户激活设备，从列表中选择报告，然后点击生成。

Some context information: the normal workflow is as following. The user activates a devices, chooses a report from a list and clicks on "generate".

编辑：感谢您的答复！对我来说很清楚，现在什么时候使用断言和什么时候做错误处理。至于错误处理，错误代码和异常都有优缺点。我想我去寻找异常（并为上述错误创建四个类），但我还没有真正相信。我总是想到意外情况的例外。一个无效的报告没有真正意想不到的。任何建议？ ：）

Thanks for the replies so far! For me it's clear now when to use asserts and when to do error-handling. As for error-handling, error codes and exceptions both have pros and cons. I think I go for exceptions (and create four classes for the above errors), but I'm not yet really convinced. I always thought of exceptions of 'unexpected situations'. An invalid report no isn't really unexpected. Any advice? :)

推荐答案

这些都有不同的目的：

• 错误代码vers。异常：异常和错误代码表示结果代码如何处理的不同习语。异常更强大 - 结果代码可以被忽略或丢失。库通常应该强烈地区分哪里/什么异常被抛出，以及何时使用错误代码。

• error code vers. exception(s): exceptions and error codes represent different idioms of how result codes shout be handled. Exceptions are more robust - result codes can be ignored or lost. A library should usually strongly distinguish where/what exceptions are thrown, and when error codes are used. At best, use only one of both at all.

返回 true 或 false ：错误代码的专门化。
通常最糟糕的想法 - 只有当没有更多的报告好或坏（即 malloc 返回好或坏（= NULL ）。

return true or false: A specialization of error codes. Usually the worst idea - only good if there is no more to report than good or bad (i.e. malloc returns either good or bad (= NULL).

assert和log：这些是调试技术，不应该用作用户/ 。

assert and log: These are debugging techniques, and should not be used as report mechanisms to users / clients. Asserts just say "something happened, that I can not handle - I quit".

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