NULL

 

C++

Linguaggio

Concetti

Libreria di Utilità

Stringhe

Contenitori

Algoritmi

Iteratori

Libreria matematca

Input/output

Localizzazione

Espressioni regolari(C++11)

Operazioni atomicche(C++11)

Multithreading(C++11)

 

Utilità libreria

Tipo di supporto (basic types, RTTI, type traits)

Gestione della memoria dinamica

La gestione degli errori

Programma di utilità

Funzioni variadic

Data e ora

Funzione oggetti

initializer_list (C++11)

bitset

hash (C++11)

Gli operatori relazionali Original: Relational operators The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

rel_ops::operator!= rel_ops::operator> rel_ops::operator<= rel_ops::operator>=

Coppie e tuple Original: Pairs and tuples The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

pair

tuple (C++11)

piecewise_construct_t (C++11)

piecewise_construct (C++11)

Swap, in avanti e spostare Original: Swap, forward and move The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

swap

forward (C++11)

move (C++11)

move_if_noexcept (C++11)

declval (C++11)

 

Tipo di supporto

Tipi base Original: Basic types The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
Tipi fondamentali
Larghezza fissa interi tipi(C++11)
ptrdiff_t size_t max_align_t (C++11)	nullptr_t (C++11) offsetof NULL
Limiti numerici Original: Numeric limits The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
numeric_limits
C numerico limita interfaccia
Informazioni sul tipo di runtime Original: Runtime type information The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
type_info type_index (C++11)	bad_typeid bad_cast
Tipo tratti Original: Type traits The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
Categorie di tipo primario Original: Primary type categories The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_void (C++11) is_array (C++11) is_pointer (C++11) is_enum (C++11) is_union (C++11) is_class (C++11) is_function (C++11)	is_object (C++11) is_scalar (C++11) is_compound (C++11) is_integral (C++11) is_floating_point (C++11) is_fundamental (C++11) is_arithmetic (C++11)
is_reference (C++11)
is_lvalue_reference (C++11)
is_rvalue_reference (C++11)
is_member_pointer (C++11)
is_member_object_pointer (C++11)
is_member_function_pointer (C++11)

Proprietà del tipo Original: Type properties The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_const (C++11) is_volatile (C++11) is_pod (C++11) is_empty (C++11) is_polymorphic (C++11) is_abstract (C++11)	is_trivial (C++11) is_trivially_copyable (C++11) is_standard_layout (C++11) is_literal_type (C++11) is_signed (C++11) is_unsigned (C++11)

Operazioni supportate Original: Supported operations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_constructible is_trivially_constructible is_nothrow_constructible (C++11) (C++11) (C++11)
is_default_constructible is_trivially_default_constructible is_nothrow_default_constructible (C++11) (C++11) (C++11)
is_copy_constructible is_trivially_copy_constructible is_nothrow_copy_constructible (C++11) (C++11) (C++11)
is_move_constructible is_trivially_move_constructible is_nothrow_move_constructible (C++11) (C++11) (C++11)
is_assignable is_trivially_assignable is_nothrow_assignable (C++11) (C++11) (C++11)
is_copy_assignable is_trivially_copy_assignable is_nothrow_copy_assignable (C++11) (C++11) (C++11)
is_move_assignable is_trivially_move_assignable is_nothrow_move_assignable (C++11) (C++11) (C++11)
is_destructible is_trivially_destructible is_nothrow_destructible (C++11) (C++11) (C++11)
has_virtual_destructor (C++11)
I rapporti e le query di proprietà Original: Relationships and property queries The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
is_same (C++11) is_base_of (C++11) is_convertible (C++11)	alignment_of (C++11) rank (C++11) extent (C++11)
Tipo modifiche Original: Type modifications The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
remove_cv remove_const remove_volatile (C++11) (C++11) (C++11) add_cv add_const add_volatile (C++11) (C++11) (C++11) make_signed (C++11) make_unsigned (C++11)	remove_reference (C++11) add_lvalue_reference add_rvalue_reference (C++11) (C++11) remove_pointer (C++11) add_pointer (C++11) remove_extent (C++11) remove_all_extents (C++11)
Tipo di trasformazioni Original: Type transformations The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
aligned_storage (C++11) aligned_union (C++11) decay (C++11) enable_if (C++11)	conditional (C++11) common_type (C++11) underlying_type (C++11) result_of (C++11)
Digitare costanti tratto Original: Type trait constants The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
integral_constant (C++11)

 

Elemento definito nell'header <cstddef>
Elemento definito nell'header <cstring>
Elemento definito nell'header <cwchar>
Elemento definito nell'header <ctime>
Elemento definito nell'header <clocale>
Elemento definito nell'header <cstdio>
#define NULL /*implementation-defined*/

Definisce la costante di puntatore nullo, che è un prvalue integrante un'espressione costante di tipo intero che restituisce zero o un prvalue di std::nullptr_t tipo. Il puntatore nullo costante può essere conversione implicita a qualsiasi tipo di puntatore, i risultati di conversione tipo nel puntatore nullo valore di quel tipo. Se la costante puntatore nullo è di tipo intero, esso può essere convertito in un tipo di prvalue std::nullptr_t.

Original:

Defines the null pointer constant, which is an integral constant expression prvalue of integer type that evaluates to zero or a prvalue of type std::nullptr_t. The null pointer constant may be conversione implicita to any pointer type; such conversion results in the null pointer value of that type. If the null pointer constant has integer type, it may be converted to a prvalue of type std::nullptr_t.

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Possibile implementazione

#define NULL 0//since C++11#define NULL nullptr

Esempio

#include <cstddef>class S;int main(){int* p = NULL;int* p2 =static_cast<std::nullptr_t>(NULL);void(*f)(int)= NULL;int S::*mp = NULL;void(S::*mfp)(int)= NULL;}

Vedi anche

nullptr	il puntatore letterale che specifica un valore nullo (C++11) valore del puntatore Original: the pointer literal which specifies a null pointer value (C++11) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
nullptr_t (C++11)	il tipo di puntatore nullo nullptr letterale Original: the type of the null pointer literal nullptr The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (typedef)