C++核心准则​E.28:避免基于全局状态的错误处理(例如errno)

E.28: Avoid error handling based on global state (e.g. errno)

E.28:避免基于全局状态的错误处理(例如errno)

Reason（原因）

Global state is hard to manage and it is easy to forget to check it. When did you last test the return value of printf()?

全局状态难于管理而且容易忘记检查。你上一次检查printf的返回值是什么是时候？

See also: Simulating RAII

参见：模仿RAII

Example, bad（反面示例）

int last_err;

void f(int n)
{
    // ...
    p = static_cast<X*>(malloc(n * sizeof(X)));
    if (!p) last_err = -1;     // error if memory is exhausted
    // ...
}

Note（注意）

C-style error handling is based on the global variable errno, so it is essentially impossible to avoid this style completely.

C风格错误处理基于全局变量errno，因此这种风格的处理方式在本质上无法避免。

Enforcement（实施建议）

Awkward.

很难。

原文链接

https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#e28-avoid-error-handling-based-on-global-state-eg-errno