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std::throw_with_nested — cppreference.com

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Déclaré dans l'en-tête `<exception>`
`template< class T > [[noreturn]] void throw_with_nested( T&& t );`		(depuis C++11)

Génère une exception de type non spécifié qui est dérivé de deux std::nested_exception et de std::remove_reference<T>::type, et construite à partir std::forward<T>(t). Le constructeur par défaut du parent nested_exception appelle std::current_exception, capturant l'objet d'exception actuellement pris en charge, le cas échéant, dans std::exception_ptr .

Original:

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.

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Si std::remove_reference<T>::type est déjà produite à partir std::nested_exception, jette tout simplement std::forward<T>(t) .

Original:

If std::remove_reference<T>::type is already derived from std::nested_exception, simply throws std::forward<T>(t).

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Exige que std::remove_reference<T>::type est CopyConstructible

Original:

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Paramètres

t

-

l'objet exception à lever

Original:

the exception object to throw

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Retourne la valeur

(Aucun)

Original:

(none)

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Exemple

Démontre la construction et la récursivité à travers un objet d'exception imbriquée

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);
    }
}

Résultat :

exception: run() failed
 exception: Couldn't open nonexistent.file
  exception: basic_ios::clear

Voir aussi


	un type mixin pour capturer et stocker les exceptions actuelles 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. (classe) [edit]

	lève l'exception d'un std::nested_exception Original: throws the exception from a std::nested_exception The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction générique) [edit]