C++核心准则E.14:使用根据目的设计的用户定制类型异常（非内置类型）

E.14: Use purpose-designed user-defined types as exceptions (not built-in types)

E.14:使用根据目的设计的用户定制类型异常（非内置类型）

Reason（原因）

A user-defined type is unlikely to clash with other people's exceptions.

用户定义类型不大可能和其他人的异常发生冲突。

Example（示例）

void my_code()
{
    // ...
    throw Moonphase_error{};
    // ...
}

void your_code()
{
    try {
        // ...
        my_code();
        // ...
    }
    catch(const Bufferpool_exhausted&) {
        // ...
    }
}

Example, don't（反面示例）

void my_code()     // Don't
{
    // ...
    throw 7;       // 7 means "moon in the 4th quarter"
    // ...
}

void your_code()   // Don't
{
    try {
        // ...
        my_code();
        // ...
    }
    catch(int i) {  // i == 7 means "input buffer too small"
        // ...
    }
}

Note（注意）

The standard-library classes derived from exception should be used only as base classes or for exceptions that require only "generic" handling. Like built-in types, their use could clash with other people's use of them.

继承自exception的标准库类应该只用于基类或只要求“通常”处理的异常。和内置类型相似，你对它们的使用可能和其他人的使用发生冲突。

Example, don't（反面示例）

void my_code()   // Don't
{
    // ...
    throw runtime_error{"moon in the 4th quarter"};
    // ...
}

void your_code()   // Don't
{
    try {
        // ...
        my_code();
        // ...
    }
    catch(const runtime_error&) {   // runtime_error means "input buffer too small"
        // ...
    }
}

See also: Discussion

参见：话题讨论

Enforcement（实施建议）

Catch throw and catch of a built-in type. Maybe warn about throw and catch using a standard-library exception type. Obviously, exceptions derived from the std::exception hierarchy are fine.

捕捉针对内置类型的throw和catch。也许可以针对使用标准库异常类型的throw和catch发出警告。显然，继承自std::exception的异常类没有问题。

原文链接

https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#e14-use-purpose-designed-user-defined-types-as-exceptions-not-built-in-types