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< cpp‎ | types

 
 
 
Soutien aux types fondamentaux
Les types de base
Original:
Basic types
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Types fondamentaux
Fixe les types entiers largeur (C++11)
nullptr_t (C++11)
offsetof
NULL
Limites numériques
Original:
Numeric limits
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numeric_limits
C numérique limite interface
Informations sur le type d'exécution
Original:
Runtime type information
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Caractères de type
Original:
Type traits
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Catégories de type primaire
Original:
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)
Les propriétés du type
Original:
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)
Opérations prises en charge
Original:
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)
(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)
Les relations et les requêtes de propriété
Original:
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)
Modifications de type
Original:
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)
Transformations de type
Original:
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)
Tapez constantes traits
Original:
Type trait constants
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integral_constant (C++11)
 
Defined in header <cstddef>
#define offsetof(type, member) /*implementation-defined*/
offsetof la macro s'étend à une constante de std::size_t type, la valeur de ce qui est le décalage en octets du début d'un objet du type spécifié à son élément de donnée, y compris le cas échéant rembourrage .
Original:
The macro offsetof expands to a constant of type std::size_t, the value of which is the offset, in bytes, from the beginning of an object of specified type to its specified member, including padding if any.
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Sommaire

[modifier] Notes

Si type n'est pas un type standard mise en page, le comportement est indéfini .
Original:
If type is not a standard-layout type, the behavior is undefined.
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Si member est un membre statique ou un membre de la fonction, le comportement est indéfini .
Original:
If member is a static member or a function member, the behavior is undefined.
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Le décalage du premier membre d'un type standard-layout est toujours zéro (vide de base de l'optimisation est obligatoire)
Original:
The offset of the first member of a standard-layout type is always zero (vide de base de l'optimisation is mandatory)
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[modifier] Mise en œuvre possible

#define offsetof(type,member) ((std::size_t) &(((type*)0)->member))

[modifier] Exemple

#include <iostream>
#include <cstddef>
struct S {
    char c;
    double d;
};
int main()
{
    std::cout << "the first element is at offset " << offsetof(S, c) << '\n'
              << "the double is at offset " << offsetof(S, d) << '\n';
}

Résultat :

the first element is at offset 0
the double is at offset 8

[modifier] Voir aussi

unsigned integer retournée par l'opérateur sizeof
Original:
unsigned integer type returned by the sizeof operator
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(typedef) [edit]
vérifie si un type est standard disposition type
Original:
checks if a type is standard-layout type
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(classe générique) [edit]