std::basic_istream::sentry
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<tbody> </tbody>| Elemento definito nell'header <istream>
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template< class CharT, class Traits = std::char_traits<CharT>> class std::basic_istream<CharT, Traits>::sentry; |
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An object of class basic_istream::sentry is constructed in local scope at the beginning of each member function of std::basic_istream that performs input (both formatted and unformatted). Its constructor prepares the input stream: checks if the stream is already in a failed state, flushes the tie()'d output streams, skips leading whitespace if skipws flag is set, and performs other implementation-defined tasks if necessary. All cleanup, if necessary, is performed in the destructor, so that it is guaranteed to happen if exceptions are thrown during input.
Membri tipi
traits_type
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Traits
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Membri funzioni
costruisce la object. All sentinella si svolgono le attività di preparazione qui Original: constructs the sentry object. All the preparation tasks are done here The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico) | |
| finalizes the stream object after formatted input or after exception, if necessary (metodo pubblico) | |
operator= [cancellato] |
Non copiare assegnabile Original: not copy assignable The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico) |
controlla se la preparazione dell'oggetto flusso ha avuto successo Original: checks if the preparation of the stream object was successful The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico) | |
Esempio
#include <iostream>
#include <sstream>
struct Foo {
char n[5];
};
std::istream& operator>>(std::istream& is, Foo& f)
{
std::istream::sentry s(is);
if(s)
is.read(f.n, 5);
return is;
}
int main()
{
std::string input = " abcde";
std::istringstream stream(input);
Foo f;
stream >> f;
std::cout.write(f.n, 5);
std::cout << '\n';
}
Output:
abcde
Vedi anche
estratti i dati formattati Original: extracts formatted data The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico) | |
estrae i caratteri e array di caratteri Original: extracts characters and character arrays 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) | |