std::rethrow_if_nested
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Elemento definito nell'header <exception> | ||
template<class E > void rethrow_if_nested(const E& e ); | (dal C++11) | |
Se
E è un tipo che è inequivocabilmente derivato da std::nested_exception, estratti e genera l'eccezione nidificata come se chiamando dynamic_cast<conststd::nested_exception&>(e).rethrow_nested(). In caso contrario, non fa nulla.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<conststd::nested_exception&>(e).rethrow_nested(). Otherwise, does nothing.The text has been machine-translated via Google Translate.
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Indice |
[modifica]Parametri
| e | - | l'oggetto eccezione di ripetere la generazione 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. |
[modifica]Valore di ritorno
(Nessuno)
Original:
(none)
The text has been machine-translated via Google Translate.
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[modifica]Esempio
Dimostra costruzione e ricorsione attraverso un oggetto eccezione nidificata
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 holdsvoid print_exception(conststd::exception& e, int level =0){std::cerr<<std::string(level, ' ')<<"exception: "<< e.what()<<'\n';try{ std::rethrow_if_nested(e);}catch(conststd::exception& e){ print_exception(e, level+1);}catch(...){}} // sample function that catches an exception and wraps it in a nested exceptionvoid open_file(conststd::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 exceptionvoid 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 exceptionint main(){try{ run();}catch(conststd::exception& e){ print_exception(e);}}
Output:
exception: run() failed exception: Couldn't open nonexistent.file exception: basic_ios::clear
[modifica]Vedi anche
(C++11) | un tipo mixin per acquisire e memorizzare le eccezioni attuali 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) |
(C++11) | lancia la sua tesi con std::nested_exception misto trovi 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. (funzione di modello) |
