std :: copy_exception在哪里定义？ [英] Where is std::copy_exception defined?

问题描述

Anthony Williams在中的 C ++并发操作 4.2.4保存将来的异常，可以直接存储异常而不使用 std :: copy_exception 抛出异常。但是我似乎找不到标准库头文件定义 std :: copy_exception 。我在哪里可以找到它？

The book C++ Concurrency in Action by Anthony Williams states in 4.2.4 Saving an exception for the future that it is possible to store an exception directly without throwing using std::copy_exception. However I seem to be unable to find the standard library header where std::copy_exception is defined. Where can I find it?

推荐答案

委员会决定名称 copy_exception （可能从 boost :: copy_exception 中复制到标准中）具有误导性，原因如下。

The committee decided that the name copy_exception (probably copied into the standard from boost::copy_exception) was misleading for the following reasons.

code> copy_exception 函数向其参数的副本返回 exception_ptr ，如同

The copy_exception function returns an exception_ptr to a copy of its argument, as if

template <class E>
exception_ptr copy_exception(E e) {
    try {
        throw e;
    } catch (...) {
        return current_exception();
    }
}

当调用 exception_ptr 作为参数，函数将返回另一个 exception_ptr 指向 exception_ptr 作为参数，而不是指向 exception_ptr 参数指向的。因为 copy_exception 对于这种情况是误导的，所以对于最终的C +，函数被重命名为 std :: make_exception_ptr +11标准。请参阅 C ++标准库缺陷报告1130

When called with an exception_ptr as argument, the function would return another exception_ptr pointing to a copy of the exception_ptr given as argument, instead of pointing to what the exception_ptr argument points to. Because the name copy_exception was misleading for this case, the function was renamed to std::make_exception_ptr for the final C++11 standard. See the C++ Standard Library Defect Report 1130 for details and discussion on this issue.

std :: make_exception_ptr 函数定义在< exception> 。

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