std::ios_base::pword
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void*& pword(int index ); | ||
Zunächst ordnet oder die private Lagerhaltung (dynamisches Array von void* oder anderen Wendeschneidplatten Datenstruktur) die Größe ausreichend, um
index gültiger Index, kehrt dann einen Verweis auf die void* Element der privaten Lagerhaltung mit dem Index index . Original:
First, allocates or resizes the private storage (dynamic array of void* or another indexable data structure) sufficiently to make
index a valid index, then returns a reference to the void* element of the private storage with the index index. The text has been machine-translated via Google Translate.
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Die Referenz kann von jedem Betrieb ungültig auf dieser
ios_base Objekt, einschließlich anderen Aufruf pword(), aber die gespeicherten Werte bleiben erhalten, so dass das Lesen von pword(index) mit dem gleichen Index später den gleichen Wert zu produzieren (bis zum nächsten Aufruf copyfmt()). Der Wert kann für jeden Zweck verwendet werden. Der Index des Elements durch xalloc() muss eingeholt werden, da sonst Kollisionen mit anderen Nutzern dieser ios_base auftreten. Neuen Elemente werden auf NULL initialisiert .Original:
The reference may be invalidated by any operation on this
ios_base object, including another call to pword(), but the stored values are retained, so that reading from pword(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 NULL.The text has been machine-translated via Google Translate.
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Wenn Allokation fehlschlägt, ruft std::basic_ios<>::setstate(badbit) die std::basic_ios::failure werfen kann
Original:
If allocation fails, calls std::basic_ios<>::setstate(badbit) which may throw std::basic_ios::failure
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Inhaltsverzeichnis |
[Bearbeiten]Parameter
| index | - | Indexwert des Elements 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. |
[Bearbeiten]Rückgabewert
Verweis auf das Element
Original:
reference to the element
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[Bearbeiten]Ausnahmen
Kann std::ios_base::failure werfen beim Einstellen der badbit .
Original:
May throw std::ios_base::failure when setting the badbit.
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[Bearbeiten]Beispiel
Verwendet Basisklasse PWord Speicher für Laufzeittyp Identifikation von abgeleiteten Stream-Objekten .
Original:
Uses base class pword storage for runtime type identification of derived stream objects.
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#include <iostream> template<class charT, class traits =std::char_traits<charT>>class mystream :publicstd::basic_ostream<charT, traits>{public:staticconstint xindex; mystream(std::basic_ostream<charT, traits>& ostr):std::basic_ostream<charT, traits>(ostr.rdbuf()){ this->pword(xindex)= this;} void myfn(){*this <<"[special handling for mystream]";}}; // each specialization of mystream obtains a unique index from xalloc()template<class charT, class traits>constint mystream<charT, traits>::xindex= std::ios_base::xalloc(); // This I/O manipulator will be able to recognize ostreams that are mystreams// by looking up the pointer stored in pwordtemplate<class charT, class traits>std::basic_ostream<charT,traits>& mymanip(std::basic_ostream<charT,traits>& os){if(os.pword(mystream<charT,traits>::xindex)==&os)static_cast<mystream<charT,traits>&>(os).myfn();return os;} int main(){std::cout<<"cout, narrow-character test "<< mymanip <<'\n'; mystream<char> myout(std::cout); myout <<"myout, narrow-character test "<< mymanip <<'\n'; std::wcout<<"wcout, wide-character test "<< mymanip <<'\n'; mystream<wchar_t> mywout(std::wcout); mywout <<"mywout, wide-character test "<< mymanip <<'\n';}
Output:
cout, narrow-character test myout, narrow-character test [special handling for mystream] wcout, wide-character test mywout, wide-character test [special handling for mystream]
[Bearbeiten]Siehe auch
die Größe der privaten Lagerhaltung bei Bedarf und Zugang zum long Element am angegebenen Index Original: resizes the private storage if necessary and access to the long 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. (öffentliche Elementfunktion) | |
[statisch] | kehrt ein Programm-weit eindeutige Zahl, die sicher als Index PWord () und iword () verwenden 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. (public static Elementfunktion) |
