Difference between revisions of "cpp/error/nested exception"
From cppreference.com
(→Example: use {{example template}}) |
m (r2.7.3) (Robot: Adding de, es, fr, it, ja, pt, ru, zh) |
||
| Line 23: | Line 23: | ||
{{dcl list template | cpp/error/dcl list exception_ptr}} | {{dcl list template | cpp/error/dcl list exception_ptr}} | ||
{{dcl list end}} | {{dcl list end}} | ||
| + | |||
| + | [[de:cpp/error/nested exception]] | ||
| + | [[es:cpp/error/nested exception]] | ||
| + | [[fr:cpp/error/nested exception]] | ||
| + | [[it:cpp/error/nested exception]] | ||
| + | [[ja:cpp/error/nested exception]] | ||
| + | [[pt:cpp/error/nested exception]] | ||
| + | [[ru:cpp/error/nested exception]] | ||
| + | [[zh:cpp/error/nested exception]] | ||
Revision as of 14:31, 2 November 2012
| Defined in header <exception>
|
||
| class nested_exception; |
(since C++11) | |
std::nested_exceptions is a polymorphic mixin class which can capture and store the current exception, making it possible to nest exceptions of arbitrary types within each other.
Member functions
| constructs a nested_exception (public member function) | |
| [virtual] |
destructs a nested exception (virtual public member function) |
| replaces the contents of a nested_exception (public member function) | |
| throws the stored exception (public member function) | |
| obtains a pointer to the stored exception (public member function) |
Example
Demonstrates construction and recursion through a nested exception object.
Run this code
#include <exception> #include <fstream> #include <iostream> #include <stdexcept> #include <string> // 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& nestedException) { print_exception(nestedException, 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); } }
Possible output:
exception: run() failed exception: Couldn't open nonexistent.file exception: basic_ios::clear
