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std::is_scalar

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Grundtypen
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Basic types
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Grundtypen
Feste Breite Integer-Typen (C++11)
Numerische Grenzen
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Numeric limits
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numeric_limits
C numerische begrenzt Schnittstelle
Laufzeit-Typinformationen
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Runtime type information
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Exterieur
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Type traits
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Primären Typ Kategorien
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Primary type categories
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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)
Typ Eigenschaften
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Type properties
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is_const(C++11)
is_volatile(C++11)
is_pod(C++11)
is_empty(C++11)
is_polymorphic(C++11)
is_abstract(C++11)
Unterstützte Operationen
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Supported operations
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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)
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(C++11)
is_copy_assignable
is_trivially_copy_assignable
is_nothrow_copy_assignable
(C++11)
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(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)
Beziehungen und Eigentum Abfragen
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Relationships and property queries
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is_same(C++11)
is_base_of(C++11)
is_convertible(C++11)
alignment_of(C++11)
rank(C++11)
extent(C++11)
Typ Modifikationen
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Type modifications
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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)
Typ Transformationen
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Type transformations
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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)
Typ-Trait-Konstanten
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Type trait constants
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integral_constant(C++11)
 
Defined in header <type_traits>
template< class T >
struct is_scalar;
(seit C++11)
Wenn T ein Skalar-Typ (das heißt, ein arithmetischer Typ, Aufzählungstyp, Zeiger, Zeiger auf ein Element oder std::nullptr_t, einschließlich etwaiger cv qualifizierte Varianten) ist, stellt das Mitglied konstanten value gleich true. Für jede andere Art, value ist false .
Original:
If T is a scalar type (that is, arithmetic type, enumeration type, pointer, pointer to member, or std::nullptr_t, including any cv-qualified variants), provides the member constant value equal true. For any other type, value is false.
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Inhaltsverzeichnis

Inherited from std::integral_constant

Member constants

value
[statisch]
true wenn T is a scalar type , false anders
Original:
true if T is a scalar type , false otherwise
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(public static Mitglied konstanten)

Member functions

operator bool
wandelt das Objekt bool, gibt value
Original:
converts the object to bool, returns value
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(öffentliche Elementfunktion)

Member types

Type
Original:
Type
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Definition
value_type bool
type std::integral_constant<bool, value>

[Bearbeiten] Notes

Jede einzelne Speicherstelle in der C + +-Speicher-Modell, einschließlich der verborgenen Speicherplätze durch Spracheigenschaften (zB virtuelle Tabellenzeiger) verwendet wird, hat skalaren Typ (oder eine Sequenz von benachbarten Bit-Bereichen nicht Null). Die Sequenzierung von Nebenwirkungen in der Auswertung eines Ausdrucks, interthread Synchronisation, und die Abhängigkeit der Bestellung sind alle in Bezug auf einzelne skalare Objekte definiert .
Original:
Each individual memory location in the C++ memory model, including the hidden memory locations used by language features (e.g virtual table pointer), has scalar type (or is a sequence of adjacent bit-fields of non-zero length). Sequencing of side-effects in expression evaluation, interthread synchronization, and dependency ordering are all defined in terms of individual scalar objects.
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[Bearbeiten] Mögliche Implementierung

template< class T >
struct is_scalar : std::integral_constant<bool,
                     std::is_arithmetic<T>::value     ||
                     std::is_enum<T>::value           ||
                     std::is_pointer<T>::value        ||
                     std::is_member_pointer<T>::value ||
                     std::is_same<std::nullptr_t, typename std::remove_cv<T>::type>::value> {};

[Bearbeiten] Beispiel

#include <iostream>
#include <type_traits>
 
int main() {
    class cls {};
    std::cout << (std::is_scalar<int>::value
                     ? "T is scalar"
                     : "T is not a scalar") << '\n';
    std::cout << (std::is_scalar<cls>::value
                     ? "T is scalar"
                     : "T is not a scalar") << '\n';
}

Output:

T is scalar
T is not a scalar

[Bearbeiten] Siehe auch

prüft, ob ein Typ ist arithmetischen Typ
Original:
checks if a type is arithmetic type
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(Klassen-Template) [edit]
(C++11)
prüft, ob eine Art ist ein Aufzählungstyp
Original:
checks if a type is an enumeration type
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(Klassen-Template) [edit]
prüft, ob ein Typ ist ein Zeiger-Typ
Original:
checks if a type is a pointer type
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(Klassen-Template) [edit]
checks if a type is a pointer to a non-static member function or object
(Klassen-Template) [edit]