std::rethrow_if_nested
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| Defined in header <exception>
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| template< class E > void rethrow_if_nested( const E& e ); |
（C++11 起） | |
如果
E是一个类型，是明确地来自std::nested_exception，提取物和抛出的嵌套异常，如果通过调用dynamic_cast<const std::nested_exception&>(e).rethrow_nested()。否则，什么都不做.Original:
If
E is a type that is unambiguously derived from std::nested_exception, extracts and throws the nested exception as if by calling dynamic_cast<const std::nested_exception&>(e).rethrow_nested(). Otherwise, does nothing.The text has been machine-translated via Google Translate.
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目录 |
[编辑] 参数
| e | - | 重新抛出的异常对象
Original: the exception object to rethrow The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
[编辑] 返回值
（无）
Original:
(none)
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[编辑] 为例
示范建设和递归，通过嵌套异常对象
Original:
Demonstrates construction and recursion through a nested exception object
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#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); } }
Output:
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 Original: a mixin type to capture and store current exceptions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （类） |
| （C++11） |
std::nested_exception混合 Original: throws its argument with std::nested_exception mixed in The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数模板） |
