如何避免SIGSEGV？ [英] How to avoid SIGSEGV?

问题描述

我正在编写一个客户端 - 服务器守护进程，它必须接受并翻译特定的消息格式，检查它们是否提交所有活动到DB。程序是多线程的。所以，我开始工作，并开始得到SIGSEGV在某些情况下。所以我不得不重新设计我的程序，从头开始。
我想知道，如果有任何最佳做法或提示如何最大限度地降低SIGSEGV的风险？
我知道，每个指针在使用之前应该检查，在删除之后应该检查NULLED，但是如果有任何高级别的设计提示？

I am writing a client-server daemon which have to accept and translate specific message formats, check them submit to submit all activity to DB. Program is multithreaded. So, I started to work, and began to get SIGSEGV in some cases. So I had to redesign my program and start all over. I am wondering, if there are any "best practices" or tips on how to minimize risk of SIGSEGV ? I know, that each pointer should be checked before usage and NULLED after deleting, but if there any high level, design tips ?

对不起，如果我的问题，如果很虚假，但我googled这个话题，没有找到任何合理的文章这个话题。

P.S. Sorry, if my question if quite dummy, but I googled for this topic and did not find any reasonable articles on this topic. All your opinions are appreciated.

推荐答案

分段错误的主要来源是

• 未初始化的指针（或一般为未初始化的变量）


• 超出对数组的访问


• 指针算术

处理这些的主要策略包括：

The main strategies to deal with this include:

• 始终初始化您的变量，特别是指针


• 避免裸指针（更喜欢智能指针，例如 std :: unique_ptr 或 std :: shared_ptr 用于拥有数据的指针，如果只想在 li>
  
• 使用标准容器（例如 std :: vector ）而不是数组和指针算术

• Always initialize your variables, in particular pointers
• Avoid naked pointers (prefer smart pointers, such as std::unique_ptr or std::shared_ptr for pointers that own data, and use iterators into standard containers if you want to merely point at stuff)
• Use standard containers (e.g. std::vector) instead of arrays and pointer arithmetics

如注释中所提到的，编码不良的并发或并行化可能会导致分段错误（和许多其他问题），与未初始化变量类似，因为它们可能导致变量意外更改。处理此问题的一般策略包括：

As mentioned in the comments, poorly coded concurrency or parallelization can cause segmentation faults (and many other problems), in a similar way as uninitialized variables can, because they may cause the value of a variable to be altered unexpectedly. General strategies to deal with this include:

• 避免共享数据–喜欢用于线程间通信的消息/队列


• 如果您有共享数据，并且至少有一个线程写入这些数据，请使用mutexes std :: atomic 或类似用于保护

• Avoid shared data – prefer messaging / queues for inter-thread communication
• If you have shared data, and at least one thread writes into those data, use mutexes, std::atomic or similar for protection

但是，在某些情况下，这两种情况都意味着您会失去显着的性能优势。正确获得并行算法是一个仔细分析和设计的问题。

However, both may in some cases mean that you loose significant performance benefits. Getting parallel algorithms right is a matter of careful analysis and design.

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