[dcl.init.general]

# 9 Declarations [[dcl]](./#dcl)

## 9.5 Initializers [[dcl.init]](dcl.init#general)

### 9.5.1 General [dcl.init.general]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L4912)

The process of initialization described in [[dcl.init]](dcl.init "9.5 Initializers") applies to
all initializations regardless of syntactic context, including the
initialization of a function parameter ([[expr.call]](expr.call "7.6.1.3 Function call")), the
initialization of a return value ([[stmt.return]](stmt.return "8.8.4 The return statement")), or when an
initializer follows a declarator[.](#1.sentence-1)

[initializer:](#nt:initializer "9.5.1 General [dcl.init.general]")  
[*brace-or-equal-initializer*](#nt:brace-or-equal-initializer "9.5.1 General [dcl.init.general]")  
( [*expression-list*](expr.post.general#nt:expression-list "7.6.1.1 General [expr.post.general]") )

[brace-or-equal-initializer:](#nt:brace-or-equal-initializer "9.5.1 General [dcl.init.general]")  
= [*initializer-clause*](#nt:initializer-clause "9.5.1 General [dcl.init.general]")  
[*braced-init-list*](#nt:braced-init-list "9.5.1 General [dcl.init.general]")

[initializer-clause:](#nt:initializer-clause "9.5.1 General [dcl.init.general]")  
[*assignment-expression*](expr.assign#nt:assignment-expression "7.6.19 Assignment and compound assignment operators [expr.assign]")  
[*braced-init-list*](#nt:braced-init-list "9.5.1 General [dcl.init.general]")

[braced-init-list:](#nt:braced-init-list "9.5.1 General [dcl.init.general]")  
{ [*initializer-list*](#nt:initializer-list "9.5.1 General [dcl.init.general]") ,opt }  
{ [*designated-initializer-list*](#nt:designated-initializer-list "9.5.1 General [dcl.init.general]") ,opt }  
{ }

[initializer-list:](#nt:initializer-list "9.5.1 General [dcl.init.general]")  
[*initializer-clause*](#nt:initializer-clause "9.5.1 General [dcl.init.general]") ...opt  
[*initializer-list*](#nt:initializer-list "9.5.1 General [dcl.init.general]") , [*initializer-clause*](#nt:initializer-clause "9.5.1 General [dcl.init.general]") ...opt

[designated-initializer-list:](#nt:designated-initializer-list "9.5.1 General [dcl.init.general]")  
[*designated-initializer-clause*](#nt:designated-initializer-clause "9.5.1 General [dcl.init.general]")  
[*designated-initializer-list*](#nt:designated-initializer-list "9.5.1 General [dcl.init.general]") , [*designated-initializer-clause*](#nt:designated-initializer-clause "9.5.1 General [dcl.init.general]")

[designated-initializer-clause:](#nt:designated-initializer-clause "9.5.1 General [dcl.init.general]")  
[*designator*](#nt:designator "9.5.1 General [dcl.init.general]") [*brace-or-equal-initializer*](#nt:brace-or-equal-initializer "9.5.1 General [dcl.init.general]")

[designator:](#nt:designator "9.5.1 General [dcl.init.general]")  
. [*identifier*](lex.name#nt:identifier "5.11 Identifiers [lex.name]")

[expr-or-braced-init-list:](#nt:expr-or-braced-init-list "9.5.1 General [dcl.init.general]")  
[*expression*](expr.comma#nt:expression "7.6.20 Comma operator [expr.comma]")  
[*braced-init-list*](#nt:braced-init-list "9.5.1 General [dcl.init.general]")

[*Note [1](#note-1)*:

The rules in [[dcl.init]](dcl.init "9.5 Initializers") apply even if the grammar permits only
the [*brace-or-equal-initializer*](#nt:brace-or-equal-initializer "9.5.1 General [dcl.init.general]") form
of [*initializer*](#nt:initializer "9.5.1 General [dcl.init.general]") in a given context[.](#1.sentence-2)

— *end note*]

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L4978)

Except for objects declared with the constexpr specifier, for which see [[dcl.constexpr]](dcl.constexpr "9.2.6 The constexpr and consteval specifiers"),
an [*initializer*](#nt:initializer "9.5.1 General [dcl.init.general]") in the definition of a variable can consist of
arbitrary expressions involving literals and previously declared
variables and functions,
regardless of the variable's storage duration[.](#2.sentence-1)

[*Example [1](#example-1)*: int f(int);int a = 2;int b = f(a);int c(b); — *end example*]

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L4993)

[*Note [2](#note-2)*:

Default arguments are more restricted; see [[dcl.fct.default]](dcl.fct.default "9.3.4.7 Default arguments")[.](#3.sentence-1)

— *end note*]

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L4998)

[*Note [3](#note-3)*:

The order of initialization of variables with static storage duration is described in [[basic.start]](basic.start "6.10.3 Start and termination") and [[stmt.dcl]](stmt.dcl "8.10 Declaration statement")[.](#4.sentence-1)

— *end note*]

[5](#5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5004)

A declaration D of a variable with linkage
shall not have an [*initializer*](#nt:initializer "9.5.1 General [dcl.init.general]") if D inhabits a block scope[.](#5.sentence-1)

[6](#6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5009)

To [*zero-initialize*](#def:zero-initialization "9.5.1 General [dcl.init.general]") an object or reference of type T means:

- [(6.1)](#6.1)

if T is std​::​meta​::​info,
the object is initialized to a null reflection value;

- [(6.2)](#6.2)

if T is any other scalar type ([[basic.types.general]](basic.types.general#term.scalar.type "6.9.1 General")),
the object is initialized to the value
obtained by converting the integer literal 0 (zero) to T;[78](#footnote-78 "As specified in [conv.ptr], converting an integer literal whose value is 0 to a pointer type results in a null pointer value.")

- [(6.3)](#6.3)

ifT is a (possibly cv-qualified) non-union class type,
its padding bits ([[basic.types.general]](basic.types.general#term.padding.bits "6.9.1 General")) are initialized to zero bits and
each non-static data member,
each non-virtual base class subobject, and,
if the object is not a base class subobject,
each virtual base class subobject
is zero-initialized;

- [(6.4)](#6.4)

ifT is a (possibly cv-qualified) union type,
its padding bits ([[basic.types.general]](basic.types.general#term.padding.bits "6.9.1 General")) are initialized to zero bits and
the
object's first non-static named
data member
is zero-initialized;

- [(6.5)](#6.5)

ifT is an array type,
each element is zero-initialized;

- [(6.6)](#6.6)

ifT is a reference type, no initialization is performed[.](#6.sentence-1)

[7](#7)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5062)

To[*default-initialize*](#def:default-initialization "9.5.1 General [dcl.init.general]") an object of typeT means:

- [(7.1)](#7.1)

  IfT is a (possibly cv-qualified) class type ([[class]](class "11 Classes")),
constructors are considered[.](#7.1.sentence-1)
  The applicable constructors are
enumerated ([[over.match.ctor]](over.match.ctor "12.2.2.4 Initialization by constructor")), and the best one for the[*initializer*](#nt:initializer "9.5.1 General [dcl.init.general]") () is chosen through
overload resolution ([[over.match]](over.match "12.2 Overload resolution"))[.](#7.1.sentence-2)
  The constructor thus selected
is called, with an empty argument list, to initialize the object[.](#7.1.sentence-3)

- [(7.2)](#7.2)

  IfT is an array type,
the semantic constraints of default-initializing a hypothetical element
shall be met and
each element is default-initialized[.](#7.2.sentence-1)

- [(7.3)](#7.3)

  If T is std​::​meta​::​info, the object is zero-initialized[.](#7.3.sentence-1)

- [(7.4)](#7.4)

  Otherwise,
no initialization is performed[.](#7.4.sentence-1)

[8](#8)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5095)

A class type T is [*const-default-constructible*](#def:const-default-constructible "9.5.1 General [dcl.init.general]") if
default-initialization of T would invoke
a user-provided constructor of T (not inherited from a base class)
or if

- [(8.1)](#8.1)

each direct non-variant non-static data member M of T has a default member initializer
or, if M is of class type X (or array thereof),X is const-default-constructible,

- [(8.2)](#8.2)

if T is a union with at least one non-static data member,
exactly one variant member has a default member initializer,

- [(8.3)](#8.3)

if T is not a union,
for each anonymous union member with at least one non-static data member (if any),
exactly one non-static data member has a default member initializer, and

- [(8.4)](#8.4)

each potentially constructed base class of T is const-default-constructible[.](#8.sentence-1)

If a program calls for the default-initialization of an object of a
const-qualified type T,T shall be std​::​meta​::​  
info or a const-default-constructible class type,
or array thereof[.](#8.sentence-2)

[9](#9)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5123)

To[*value-initialize*](#def:value-initialization "9.5.1 General [dcl.init.general]") an object of typeT means:

- [(9.1)](#9.1)

  IfT is a (possibly cv-qualified) class type ([[class]](class "11 Classes")), then
let C be the constructor selected to
default-initialize the object, if any[.](#9.1.sentence-1)
  If C is not user-provided, the object is first zero-initialized[.](#9.1.sentence-2)
  In all cases, the object is then default-initialized[.](#9.1.sentence-3)

- [(9.2)](#9.2)

  IfT is an array type,
the semantic constraints of value-initializing a hypothetical element
shall be met and
each element is value-initialized[.](#9.2.sentence-1)

- [(9.3)](#9.3)

  Otherwise, the object is zero-initialized[.](#9.3.sentence-1)

[10](#10)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5152)

A program that calls for default-initialization
or value-initialization
of an entity
of reference type is ill-formed[.](#10.sentence-1)

[11](#11)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5158)

[*Note [4](#note-4)*:

For every object with static storage duration,
static initialization ([[basic.start.static]](basic.start.static "6.10.3.2 Static initialization")) is performed
at program startup before any other initialization takes place[.](#11.sentence-1)

In some cases, additional initialization is done later[.](#11.sentence-2)

— *end note*]

[12](#12)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5166)

If no initializer is specified for an object, the object is default-initialized[.](#12.sentence-1)

[13](#13)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5169)

If the entity being initialized does not have class or array type, the[*expression-list*](expr.post.general#nt:expression-list "7.6.1.1 General [expr.post.general]") in a
parenthesized initializer shall be a single expression[.](#13.sentence-1)

[14](#14)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5174)

The initialization that occurs in the = form of a[*brace-or-equal-initializer*](#nt:brace-or-equal-initializer "9.5.1 General [dcl.init.general]") or[*condition*](stmt.pre#nt:condition "8.1 Preamble [stmt.pre]") ([[stmt.select]](stmt.select "8.5 Selection statements")),
as well as in argument passing, function return,
throwing an exception ([[except.throw]](except.throw "14.2 Throwing an exception")),
handling an exception ([[except.handle]](except.handle "14.4 Handling an exception")),
and aggregate member initialization other than by a[*designated-initializer-clause*](#nt:designated-initializer-clause "9.5.1 General [dcl.init.general]") ([[dcl.init.aggr]](dcl.init.aggr "9.5.2 Aggregates")),
is called[*copy-initialization*](#def:copy-initialization "9.5.1 General [dcl.init.general]")[.](#14.sentence-1)

[*Note [5](#note-5)*:

Copy-initialization can invoke a move ([[class.copy.ctor]](class.copy.ctor "11.4.5.3 Copy/move constructors"))[.](#14.sentence-2)

— *end note*]

[15](#15)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5191)

The initialization that occurs

- [(15.1)](#15.1)

for an [*initializer*](#nt:initializer "9.5.1 General [dcl.init.general]") that is a
parenthesized [*expression-list*](expr.post.general#nt:expression-list "7.6.1.1 General [expr.post.general]") or a [*braced-init-list*](#nt:braced-init-list "9.5.1 General [dcl.init.general]"),

- [(15.2)](#15.2)

for a [*new-initializer*](expr.new#nt:new-initializer "7.6.2.8 New [expr.new]") ([[expr.new]](expr.new "7.6.2.8 New")),

- [(15.3)](#15.3)

in a static_cast expression ([[expr.static.cast]](expr.static.cast "7.6.1.9 Static cast")),

- [(15.4)](#15.4)

in a functional notation type conversion ([[expr.type.conv]](expr.type.conv "7.6.1.4 Explicit type conversion (functional notation)")), and

- [(15.5)](#15.5)

in the [*braced-init-list*](#nt:braced-init-list "9.5.1 General [dcl.init.general]") form of a [*condition*](stmt.pre#nt:condition "8.1 Preamble [stmt.pre]")

is called[*direct-initialization*](#def:direct-initialization "9.5.1 General [dcl.init.general]")[.](#15.sentence-1)

[16](#16)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5204)

The semantics of initializers are as follows[.](#16.sentence-1)

The[*destination type*](#def:destination_type) is the cv-unqualified type of the object or reference being initialized and the[*source type*](#def:source_type) is the type of the initializer expression[.](#16.sentence-2)

If the initializer is not a single (possibly parenthesized) expression, the
source type is not defined[.](#16.sentence-3)

- [(16.1)](#16.1)

  If the initializer is a (non-parenthesized) [*braced-init-list*](#nt:braced-init-list "9.5.1 General [dcl.init.general]") or is = [*braced-init-list*](#nt:braced-init-list "9.5.1 General [dcl.init.general]"), the object or reference
is list-initialized ([[dcl.init.list]](dcl.init.list "9.5.5 List-initialization"))[.](#16.1.sentence-1)

- [(16.2)](#16.2)

  If the destination type is a reference type, see [[dcl.init.ref]](dcl.init.ref "9.5.4 References")[.](#16.2.sentence-1)

- [(16.3)](#16.3)

  If the destination type is an array of characters,
an array of char8_t,
an array of char16_t,
an array of char32_t,
or an array ofwchar_t,
and the initializer is a [*string-literal*](lex.string#nt:string-literal "5.13.5 String literals [lex.string]"), see [[dcl.init.string]](dcl.init.string "9.5.3 Character arrays")[.](#16.3.sentence-1)

- [(16.4)](#16.4)

  If the initializer is (), the object is value-initialized[.](#16.4.sentence-1)
  [*Note [6](#note-6)*:
  Since() is not permitted by the syntax for[*initializer*](#nt:initializer "9.5.1 General [dcl.init.general]"),X a(); is not the declaration of an object of classX,
but the declaration of a function taking no arguments and returning anX[.](#16.4.sentence-2)
  The form() can appear in certain other initialization contexts ([[expr.new]](expr.new "7.6.2.8 New"), [[expr.type.conv]](expr.type.conv "7.6.1.4 Explicit type conversion (functional notation)"), [[class.base.init]](class.base.init "11.9.3 Initializing bases and members"))[.](#16.4.sentence-3)
 — *end note*]

- [(16.5)](#16.5)

  Otherwise, if the destination type is an array,
the object is initialized as follows[.](#16.5.sentence-1)
  The [*initializer*](#nt:initializer "9.5.1 General [dcl.init.general]") shall be of the form( [*expression-list*](expr.post.general#nt:expression-list "7.6.1.1 General [expr.post.general]") )[.](#16.5.sentence-2)
  Let x1, …, xk be
the elements of the [*expression-list*](expr.post.general#nt:expression-list "7.6.1.1 General [expr.post.general]")[.](#16.5.sentence-3)
  If the destination type is an array of unknown bound,
it is defined as having k elements[.](#16.5.sentence-4)
  Let n denote the array size after this potential adjustment[.](#16.5.sentence-5)
  If k is greater than n,
the program is ill-formed[.](#16.5.sentence-6)
  Otherwise, the ith array element is copy-initialized withxi for each 1 ≤ i ≤ k, and
value-initialized for each k<i≤n[.](#16.5.sentence-7)
  For each 1≤i<j≤n,
every value computation and side effect associated with
the initialization of the ith element of the array
is sequenced before those associated with
the initialization of the jth element[.](#16.5.sentence-8)

- [(16.6)](#16.6)

  Otherwise, if the destination type is a class type:
  * [(16.6.1)](#16.6.1)

      If the initializer expression is a prvalue
and the cv-unqualified version of the source type
is the same as the destination type,
the initializer expression is used to initialize the destination object[.](#16.6.1.sentence-1)
      [*Example [2](#example-2)*:
      T x = T(T(T())); value-initializes x[.](#16.6.1.sentence-2)
 — *end example*]

  * [(16.6.2)](#16.6.2)

      Otherwise, if the initialization is direct-initialization,
or if it is copy-initialization where the cv-unqualified version of the source
type is the same as or is derived from the class of the destination type,
constructors are considered[.](#16.6.2.sentence-1)
      The applicable constructors
are enumerated ([[over.match.ctor]](over.match.ctor "12.2.2.4 Initialization by constructor")), and the best one is chosen
through overload resolution ([[over.match]](over.match "12.2 Overload resolution"))[.](#16.6.2.sentence-2)
      Then:
    +
          [(16.6.2.1)](#16.6.2.1)
          If overload resolution is successful,
the selected constructor
is called to initialize the object, with the initializer
expression or [*expression-list*](expr.post.general#nt:expression-list "7.6.1.1 General [expr.post.general]") as its argument(s)[.](#16.6.2.1.sentence-1)

    +
          [(16.6.2.2)](#16.6.2.2)
          Otherwise, if no constructor is viable,
the destination type is
an aggregate class, and
the initializer is a parenthesized [*expression-list*](expr.post.general#nt:expression-list "7.6.1.1 General [expr.post.general]"),
the object is initialized as follows[.](#16.6.2.2.sentence-1)
          Let e1, …, en be the elements of the aggregate ([[dcl.init.aggr]](dcl.init.aggr "9.5.2 Aggregates"))[.](#16.6.2.2.sentence-2)
          Let x1, …, xk be the elements of the [*expression-list*](expr.post.general#nt:expression-list "7.6.1.1 General [expr.post.general]")[.](#16.6.2.2.sentence-3)
          If k is greater than n, the program is ill-formed[.](#16.6.2.2.sentence-4)
          The element ei is copy-initialized withxi for 1 ≤ i ≤ k[.](#16.6.2.2.sentence-5)
          The remaining elements are initialized with
their default member initializers, if any, and
otherwise are value-initialized[.](#16.6.2.2.sentence-6)
          For each 1≤i<j≤n,
every value computation and side effect
associated with the initialization of ei is sequenced before those associated with the initialization of ej[.](#16.6.2.2.sentence-7)
          [*Note [7](#note-7)*:
          By contrast with direct-list-initialization,
narrowing conversions ([[dcl.init.list]](dcl.init.list "9.5.5 List-initialization")) can appear,
designators are not permitted,
a temporary object bound to a reference
does not have its lifetime extended ([[class.temporary]](class.temporary "6.8.7 Temporary objects")), and
there is no brace elision[.](#16.6.2.2.sentence-8)
          [*Example [3](#example-3)*: struct A {int a; int&& r;};

            int f();int n = 10;

            A a1{1, f()}; // OK, lifetime is extended A a2(1, f()); // well-formed, but dangling reference A a3{1.0, 1}; // error: narrowing conversion A a4(1.0, 1); // well-formed, but dangling reference A a5(1.0, std::move(n)); // OK — *end example*]
 — *end note*]

    +
          [(16.6.2.3)](#16.6.2.3)
          Otherwise, the initialization is ill-formed[.](#16.6.2.3.sentence-1)

  * [(16.6.3)](#16.6.3)

      Otherwise (i.e., for the remaining copy-initialization cases),
user-defined conversions that can convert from the
source type to the destination type or (when a conversion function
is used) to a derived class thereof are enumerated as described in [[over.match.copy]](over.match.copy "12.2.2.5 Copy-initialization of class by user-defined conversion"),
and the best one is chosen through overload resolution ([[over.match]](over.match "12.2 Overload resolution"))[.](#16.6.3.sentence-1)
      If the conversion cannot be done or
is ambiguous, the initialization is ill-formed[.](#16.6.3.sentence-2)
      The function
selected is called with the initializer expression as its
argument; if the function is a constructor, the call is a prvalue
of the cv-unqualified version of the
destination type whose result object is initialized by the constructor[.](#16.6.3.sentence-3)
      The call is used
to direct-initialize, according to the rules above, the object
that is the destination of the copy-initialization[.](#16.6.3.sentence-4)

- [(16.7)](#16.7)

  Otherwise, if the source type
is a (possibly cv-qualified) class type, conversion functions are
considered[.](#16.7.sentence-1)
  The applicable conversion functions are enumerated ([[over.match.conv]](over.match.conv "12.2.2.6 Initialization by conversion function")),
and the best one is chosen through overload
resolution ([[over.match]](over.match "12.2 Overload resolution"))[.](#16.7.sentence-2)
  The user-defined conversion so selected
is called to convert the initializer expression into the
object being initialized[.](#16.7.sentence-3)
  If the conversion cannot be done or is
ambiguous, the initialization is ill-formed[.](#16.7.sentence-4)

- [(16.8)](#16.8)

  Otherwise, if the initialization is direct-initialization,
the source type is std​::​nullptr_t, and
the destination type is bool,
the initial value of the object being initialized is false[.](#16.8.sentence-1)

- [(16.9)](#16.9)

  Otherwise, the initial value of the object being initialized is
the (possibly converted) value of the initializer expression[.](#16.9.sentence-1)
  A standard conversion sequence ([[conv]](conv "7.3 Standard conversions")) is used
to convert the initializer expression to
a prvalue of
the destination type;
no user-defined conversions are considered[.](#16.9.sentence-2)
  If the conversion cannot
be done, the initialization is ill-formed[.](#16.9.sentence-3)
  When initializing a bit-field with a value that it cannot represent, the
resulting value of the bit-field isimplementation-defined[.](#16.9.sentence-4)
  [*Note [8](#note-8)*:
  An expression of type
“*cv1* T”
can initialize an object of type
“*cv2* T”
independently of
the cv-qualifiers*cv1* and *cv2*[.](#16.9.sentence-5)
  int a;const int b = a;int c = b; — *end note*]

[17](#17)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5407)

An immediate invocation ([[expr.const]](expr.const "7.7 Constant expressions")) that is not evaluated where
it appears ([[dcl.fct.default]](dcl.fct.default "9.3.4.7 Default arguments"), [[class.mem.general]](class.mem.general "11.4.1 General"))
is evaluated and checked for whether it is
a constant expression at the point where
the enclosing [*initializer*](#nt:initializer "9.5.1 General [dcl.init.general]") is used in
a function call, a constructor definition, or an aggregate initialization[.](#17.sentence-1)

[18](#18)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5415)

An [*initializer-clause*](#nt:initializer-clause "9.5.1 General [dcl.init.general]") followed by an ellipsis is a
pack expansion ([[temp.variadic]](temp.variadic "13.7.4 Variadic templates"))[.](#18.sentence-1)

[19](#19)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5419)

Initialization includes
the evaluation of all subexpressions of
each [*initializer-clause*](#nt:initializer-clause "9.5.1 General [dcl.init.general]") of
the initializer (possibly nested within [*braced-init-list*](#nt:braced-init-list "9.5.1 General [dcl.init.general]")*s*) and
the creation of any temporary objects for
function arguments or return values ([[class.temporary]](class.temporary "6.8.7 Temporary objects"))[.](#19.sentence-1)

[20](#20)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5427)

If the initializer is a parenthesized [*expression-list*](expr.post.general#nt:expression-list "7.6.1.1 General [expr.post.general]"),
the expressions are evaluated in the order
specified for function calls ([[expr.call]](expr.call "7.6.1.3 Function call"))[.](#20.sentence-1)

[21](#21)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5432)

The same [*identifier*](lex.name#nt:identifier "5.11 Identifiers [lex.name]") shall not appear in multiple [*designator*](#nt:designator "9.5.1 General [dcl.init.general]")*s* of a[*designated-initializer-list*](#nt:designated-initializer-list "9.5.1 General [dcl.init.general]")[.](#21.sentence-1)

[22](#22)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5437)

An object whose initialization has completed
is deemed to be constructed,
even if the object is of non-class type or
no constructor of the object's class
is invoked for the initialization[.](#22.sentence-1)

[*Note [9](#note-9)*:

Such an object might have been value-initialized
or initialized by aggregate initialization ([[dcl.init.aggr]](dcl.init.aggr "9.5.2 Aggregates"))
or by an inherited constructor ([[class.inhctor.init]](class.inhctor.init "11.9.4 Initialization by inherited constructor"))[.](#22.sentence-2)

— *end note*]

Destroying an object of class type invokes the destructor of the class[.](#22.sentence-3)

Destroying a scalar type has no effect other than
ending the lifetime of the object ([[basic.life]](basic.life "6.8.4 Lifetime"))[.](#22.sentence-4)

Destroying an array destroys each element in reverse subscript order[.](#22.sentence-5)

[23](#23)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L5453)

A declaration that specifies the initialization of a variable,
whether from an explicit initializer or by default-initialization,
is called the [*initializing declaration*](#def:initializing_declaration "9.5.1 General [dcl.init.general]") of that variable[.](#23.sentence-1)

[*Note [10](#note-10)*:

In most cases
this is the defining declaration ([[basic.def]](basic.def "6.2 Declarations and definitions")) of the variable,
but the initializing declaration
of a non-inline static data member ([[class.static.data]](class.static.data "11.4.9.3 Static data members"))
can be the declaration within the class definition
and not the definition (if any) outside it[.](#23.sentence-2)

— *end note*]

[78)](#footnote-78)[78)](#footnoteref-78)

As specified in [[conv.ptr]](conv.ptr "7.3.12 Pointer conversions"), converting an integer
literal whose value is0 to a pointer type results in a null pointer value[.](#footnote-78.sentence-1)