std::ios_base::iword
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| long& iword( int index ); |
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La première, affecte ou redimensionne le stockage privé (tableau dynamique de long ou une autre structure de données amovible) suffisamment pour faire
index un indice valide, puis renvoie une référence à l'élément de long le stockage privé à l'indice index . Original:
First, allocates or resizes the private storage (dynamic array of long or another indexable data structure) sufficiently to make
index a valid index, then returns a reference to the long element of the private storage with the index index. The text has been machine-translated via Google Translate.
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La référence peut être invalidé par une opération sur cet objet
ios_base, y compris un autre appel à iword(), mais les valeurs enregistrées sont conservées, de sorte que la lecture de iword(index) avec le même indice plus tard, va produire la même valeur (jusqu'à ce que le prochain appel à copyfmt()). La valeur peut être utilisée pour n'importe quel but. L'indice de l'élément doit être obtenu par xalloc(), sinon les collisions avec les autres utilisateurs de ce ios_base peut se produire. De nouveaux éléments sont initialisés à 0 .Original:
The reference may be invalidated by any operation on this
ios_base object, including another call to iword(), but the stored values are retained, so that reading from iword(index) with the same index later will produce the same value (until the next call to copyfmt()). The value can be used for any purpose. The index of the element must be obtained by xalloc(), otherwise collisions with other users of this ios_base may occur. New elements are initialized to 0.The text has been machine-translated via Google Translate.
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Si l'allocation échoue, appelle std::basic_ios<>::setstate(badbit) qui peut std::basic_ios::failure jeter
Original:
If allocation fails, calls std::basic_ios<>::setstate(badbit) which may throw std::basic_ios::failure
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Sommaire |
[modifier] Notes
Une utilisation typique de stockage iword est de transmettre des informations (par exemple des drapeaux en forme personnalisées) définies par l'utilisateur E / S manipulateurs définis par l'utilisateur
operator<< et operator>> ou définie par l'utilisateur facettes de mise en forme imprégnée dans les cours standard .Original:
Typical use of iword storage is to pass information (e.g. custom formatting flags) from user-defined I/O manipulators to user-defined
operator<< and operator>> or to user-defined formatting facets imbued into standard streams.The text has been machine-translated via Google Translate.
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[modifier] Paramètres
| index | - | valeur de l'indice de l'élément
Original: index value of the element The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
[modifier] Retourne la valeur
une référence à l'élément
Original:
reference to the element
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[modifier] Exceptions
Peut générer std::ios_base::failure lors du réglage du BadBit .
Original:
May throw std::ios_base::failure when setting the badbit.
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[modifier] Exemple
#include <iostream> #include <string> struct Foo { static int foo_xalloc; std::string data; Foo(const std::string& s) : data(s) {} }; // allocates the iword storage for use with Foo objects int Foo::foo_xalloc = std::ios_base::xalloc(); // This user-defined operator<< prints the string in reverse if the iword holds 1 std::ostream& operator<<(std::ostream& os, Foo& f) { if(os.iword(Foo::foo_xalloc) == 1) return os << std::string(f.data.rbegin(), f.data.rend()); else return os << f.data; } // This I/O manipulator flips the number stored in iword between 0 and 1 std::ios_base& rev(std::ios_base& os) { os.iword(Foo::foo_xalloc) = !os.iword(Foo::foo_xalloc); return os; } int main() { Foo f("example"); std::cout << f << '\n' << rev << f << '\n' << rev << f << '\n'; }
Résultat :
example elpmaxe example
[modifier] Voir aussi
| redimensionne le stockage privé et le cas échéant un accès à l'élément de void* à l'index donné Original: resizes the private storage if necessary and access to the void* element at the given index The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction membre publique) | |
| [ statique ]Original: static The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
renvoie un entier ensemble du programme unique qui est sûr à utiliser comme indice de motpasse () et iword () Original: returns a program-wide unique integer that is safe to use as index to pword() and iword() The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (fonction membre publique statique) |
