std::throw_with_nested
来自cppreference.com
该页由英文版wiki使用Google Translate机器翻译而来。
该翻译可能存在错误或用词不当。鼠标停留在文本上可以看到原版本。你可以帮助我们修正错误或改进翻译。参见说明请点击这里. |
在头文件 <exception> 中定义
|
||
template< class T > [[noreturn]] void throw_with_nested( T&& t ); |
(C++11 起) | |
来自都std::nested_exception和std::remove_reference<T>::type的,构建从std::forward<T>(t)抛出一个异常的类型不明确。默认的构造函数的父的nested_exception调用std::current_exception,捕捉当前处理的异常对象,如果有的话,std::exception_ptr.
原文:
Throws an exception of unspecified type that is derived from both std::nested_exception and from std::remove_reference<T>::type, and constructed from std::forward<T>(t). The default constructor of the nested_exception parent calls std::current_exception, capturing the currently handled exception object, if any, in std::exception_ptr.
std::remove_reference<T>::type来自std::nested_exception,简单地抛出std::forward<T>(t).
原文:
If std::remove_reference<T>::type is already derived from std::nested_exception, simply throws std::forward<T>(t).
需要std::remove_reference<T>::type是
CopyConstructible
原文:
Requires that std::remove_reference<T>::type is
CopyConstructible
目录 |
[编辑] 参数
t | - | 抛出的异常对象
|
[编辑] 返回值
(无)
[编辑] 示例
示范建设和递归,通过嵌套异常对象
原文:
Demonstrates construction and recursion through a nested exception object
#include <iostream> #include <stdexcept> #include <exception> #include <string> #include <fstream> // prints the explanatory string of an exception. If the exception is nested, // recurses to print the explanatory of the exception it holds void print_exception(const std::exception& e, int level = 0) { std::cerr << std::string(level, ' ') << "exception: " << e.what() << '\n'; try { std::rethrow_if_nested(e); } catch(const std::exception& e) { print_exception(e, level+1); } catch(...) {} } // sample function that catches an exception and wraps it in a nested exception void open_file(const std::string& s) { try { std::ifstream file(s); file.exceptions(std::ios_base::failbit); } catch(...) { std::throw_with_nested( std::runtime_error("Couldn't open " + s) ); } } // sample function that catches an exception and wraps it in a nested exception void run() { try { open_file("nonexistent.file"); } catch(...) { std::throw_with_nested( std::runtime_error("run() failed") ); } } // runs the sample function above and prints the caught exception int main() { try { run(); } catch(const std::exception& e) { print_exception(e); } }
输出:
exception: run() failed exception: Couldn't open nonexistent.file exception: basic_ios::clear
[编辑] 另请参阅
(C++11) |
一个mixin捕获和存储当前的异常的类型 原文: a mixin type to capture and store current exceptions (类) |
(C++11) |
从std::nested_exception抛出的异常 原文: throws the exception from a std::nested_exception (函数模板) |