cppdraft_translate/cppdraft/dcl/meaning/general.md

[dcl.meaning.general]

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

## 9.3 Declarators [[dcl.decl]](dcl.decl#dcl.meaning.general)

### 9.3.4 Meaning of declarators [[dcl.meaning]](dcl.meaning#general)

#### 9.3.4.1 General [dcl.meaning.general]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L2782)

A declarator contains exactly one [*declarator-id*](dcl.decl.general#nt:declarator-id "9.3.1 General [dcl.decl.general]");
it names the entity that is declared[.](#1.sentence-1)

If the [*unqualified-id*](expr.prim.id.unqual#nt:unqualified-id "7.5.5.2 Unqualified names [expr.prim.id.unqual]") occurring in a [*declarator-id*](dcl.decl.general#nt:declarator-id "9.3.1 General [dcl.decl.general]") is a [*template-id*](temp.names#nt:template-id "13.3 Names of template specializations [temp.names]"),
the declarator shall appear in the [*declaration*](dcl.pre#nt:declaration "9.1 Preamble [dcl.pre]") of a[*template-declaration*](temp.pre#nt:template-declaration "13.1 Preamble [temp.pre]") ([[temp.decls]](temp.decls "13.7 Template declarations")),[*explicit-specialization*](temp.expl.spec#nt:explicit-specialization "13.9.4 Explicit specialization [temp.expl.spec]") ([[temp.expl.spec]](temp.expl.spec "13.9.4 Explicit specialization")), or[*explicit-instantiation*](temp.explicit#nt:explicit-instantiation "13.9.3 Explicit instantiation [temp.explicit]") ([[temp.explicit]](temp.explicit "13.9.3 Explicit instantiation"))[.](#1.sentence-2)

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

An [*unqualified-id*](expr.prim.id.unqual#nt:unqualified-id "7.5.5.2 Unqualified names [expr.prim.id.unqual]") that is not an [*identifier*](lex.name#nt:identifier "5.11 Identifiers [lex.name]") is used to declare
certain functions ([[class.conv.fct]](class.conv.fct "11.4.8.3 Conversion functions"), [[class.dtor]](class.dtor "11.4.7 Destructors"), [[over.oper]](over.oper "12.4 Overloaded operators"), [[over.literal]](over.literal "12.6 User-defined literals"))[.](#1.sentence-3)

— *end note*]

The optional [*attribute-specifier-seq*](dcl.attr.grammar#nt:attribute-specifier-seq "9.13.1 Attribute syntax and semantics [dcl.attr.grammar]") following a [*declarator-id*](dcl.decl.general#nt:declarator-id "9.3.1 General [dcl.decl.general]") appertains to the entity that is declared[.](#1.sentence-4)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L2799)

If the declaration is a friend declaration:

- [(2.1)](#2.1)

  The [*declarator*](dcl.decl.general#nt:declarator "9.3.1 General [dcl.decl.general]") does not bind a name[.](#2.1.sentence-1)

- [(2.2)](#2.2)

  If the [*id-expression*](expr.prim.id.general#nt:id-expression "7.5.5.1 General [expr.prim.id.general]") E in
the [*declarator-id*](dcl.decl.general#nt:declarator-id "9.3.1 General [dcl.decl.general]") of the [*declarator*](dcl.decl.general#nt:declarator "9.3.1 General [dcl.decl.general]") is
a [*qualified-id*](expr.prim.id.qual#nt:qualified-id "7.5.5.3 Qualified names [expr.prim.id.qual]") or a [*template-id*](temp.names#nt:template-id "13.3 Names of template specializations [temp.names]"):
  * [(2.2.1)](#2.2.1)

      If the friend declaration is not a template declaration,
then in the lookup for the terminal name of E:
    +
          [(2.2.1.1)](#2.2.1.1)
if the [*unqualified-id*](expr.prim.id.unqual#nt:unqualified-id "7.5.5.2 Unqualified names [expr.prim.id.unqual]") in E is a [*template-id*](temp.names#nt:template-id "13.3 Names of template specializations [temp.names]"),
all function declarations are discarded;

    +
          [(2.2.1.2)](#2.2.1.2)
otherwise,
if the [*declarator*](dcl.decl.general#nt:declarator "9.3.1 General [dcl.decl.general]") corresponds ([[basic.scope.scope]](basic.scope.scope "6.4.1 General")) to
any declaration found of a non-template function,
all function template declarations are discarded;

    +
          [(2.2.1.3)](#2.2.1.3)
each remaining function template is replaced with the specialization chosen by
deduction from the friend declaration ([[temp.deduct.decl]](temp.deduct.decl "13.10.3.7 Deducing template arguments from a function declaration")) or
discarded if deduction fails[.](#2.2.1.sentence-1)

  * [(2.2.2)](#2.2.2)

      The [*declarator*](dcl.decl.general#nt:declarator "9.3.1 General [dcl.decl.general]") shall correspond to
one or more declarations found by the lookup;
they shall all have the same target scope, and
the target scope of the [*declarator*](dcl.decl.general#nt:declarator "9.3.1 General [dcl.decl.general]") is that scope[.](#2.2.2.sentence-1)

- [(2.3)](#2.3)

  Otherwise, the terminal name of E is not looked up[.](#2.3.sentence-1)
  The declaration's target scope is the innermost enclosing namespace scope;
if the declaration is contained by a block scope,
the declaration shall correspond to a reachable ([[module.reach]](module.reach "10.7 Reachability")) declaration
that inhabits the innermost block scope[.](#2.3.sentence-2)

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L2840)

Otherwise:

- [(3.1)](#3.1)

  If the [*id-expression*](expr.prim.id.general#nt:id-expression "7.5.5.1 General [expr.prim.id.general]") in
the [*declarator-id*](dcl.decl.general#nt:declarator-id "9.3.1 General [dcl.decl.general]") of the [*declarator*](dcl.decl.general#nt:declarator "9.3.1 General [dcl.decl.general]") is
a [*qualified-id*](expr.prim.id.qual#nt:qualified-id "7.5.5.3 Qualified names [expr.prim.id.qual]") Q,
let S be its lookup context ([[basic.lookup.qual]](basic.lookup.qual "6.5.5 Qualified name lookup"));
the declaration shall inhabit a namespace scope[.](#3.1.sentence-1)

- [(3.2)](#3.2)

  Otherwise, let S be the entity associated with the scope inhabited by
the [*declarator*](dcl.decl.general#nt:declarator "9.3.1 General [dcl.decl.general]")[.](#3.2.sentence-1)

- [(3.3)](#3.3)

  If the [*declarator*](dcl.decl.general#nt:declarator "9.3.1 General [dcl.decl.general]") declares
an explicit instantiation or a partial or explicit specialization,
the [*declarator*](dcl.decl.general#nt:declarator "9.3.1 General [dcl.decl.general]") does not bind a name[.](#3.3.sentence-1)
  If it declares a class member,
the terminal name of the [*declarator-id*](dcl.decl.general#nt:declarator-id "9.3.1 General [dcl.decl.general]") is not looked up;
otherwise, only those lookup results that are nominable in S are considered when identifying
any function template specialization being declared ([[temp.deduct.decl]](temp.deduct.decl "13.10.3.7 Deducing template arguments from a function declaration"))[.](#3.3.sentence-2)
  [*Example [1](#example-1)*: namespace N {inline namespace O {template<class T> void f(T); // #1template<class T> void g(T) {}}namespace P {template<class T> void f(T*); // #2, more specialized than #1template<class> int g; }using P::f,P::g;}template<> void N::f(int*) {} // OK, #2 is not nominabletemplate void N::g(int); // error: lookup is ambiguous — *end example*]

- [(3.4)](#3.4)

  Otherwise,
the terminal name of the [*declarator-id*](dcl.decl.general#nt:declarator-id "9.3.1 General [dcl.decl.general]") is not looked up[.](#3.4.sentence-1)
  If it is a qualified name,
the [*declarator*](dcl.decl.general#nt:declarator "9.3.1 General [dcl.decl.general]") shall correspond to
one or more declarations nominable in S;
all the declarations shall have the same target scope and
the target scope of the [*declarator*](dcl.decl.general#nt:declarator "9.3.1 General [dcl.decl.general]") is that scope[.](#3.4.sentence-2)
  [*Example [2](#example-2)*: namespace Q {namespace V {void f(); }void V::f() { /* ... */ } // OKvoid V::g() { /* ... */ } // error: g() is not yet a member of Vnamespace V {void g(); }}namespace R {void Q::V::g() { /* ... */ } // error: R doesn't enclose Q} — *end example*]

- [(3.5)](#3.5)

  If the declaration inhabits a block scope S and
declares a function ([[dcl.fct]](dcl.fct "9.3.4.6 Functions")) or uses the extern specifier,
the declaration shall not be attached to a named module ([[module.unit]](module.unit "10.1 Module units and purviews"));
its target scope is the innermost enclosing namespace scope,
but the name is bound in S[.](#3.5.sentence-1)
  [*Example [3](#example-3)*: namespace X {void p() { q(); // error: q not yet declaredextern void q(); // q is a member of namespace Xextern void r(); // r is a member of namespace X}void middle() { q(); // error: q not found}void q() { /* ... */ } // definition of X​::​q}void q() { /* ... */ } // some other, unrelated qvoid X::r() { /* ... */ } // error: r cannot be declared by [*qualified-id*](expr.prim.id.qual#nt:qualified-id "7.5.5.3 Qualified names [expr.prim.id.qual]") — *end example*]

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L2932)

Astatic,thread_local,extern,mutable,friend,inline,virtual,constexpr,consteval,constinit,
ortypedef specifier
or an [*explicit-specifier*](dcl.fct.spec#nt:explicit-specifier "9.2.3 Function specifiers [dcl.fct.spec]") applies directly to each [*declarator-id*](dcl.decl.general#nt:declarator-id "9.3.1 General [dcl.decl.general]") in a declaration;
the type specified for each [*declarator-id*](dcl.decl.general#nt:declarator-id "9.3.1 General [dcl.decl.general]") depends on
both the [*decl-specifier-seq*](dcl.spec.general#nt:decl-specifier-seq "9.2.1 General [dcl.spec.general]") and its [*declarator*](dcl.decl.general#nt:declarator "9.3.1 General [dcl.decl.general]")[.](#4.sentence-1)

[5](#5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L2953)

Thus, (for each [*declarator*](dcl.decl.general#nt:declarator "9.3.1 General [dcl.decl.general]")) a declaration has the formT D whereT is of the form [*attribute-specifier-seq*](dcl.attr.grammar#nt:attribute-specifier-seq "9.13.1 Attribute syntax and semantics [dcl.attr.grammar]")opt[*decl-specifier-seq*](dcl.spec.general#nt:decl-specifier-seq "9.2.1 General [dcl.spec.general]") andD is a declarator[.](#5.sentence-1)

Following is a recursive procedure for determining
the type specified for the contained[*declarator-id*](dcl.decl.general#nt:declarator-id "9.3.1 General [dcl.decl.general]") by such a declaration[.](#5.sentence-2)

[6](#6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L2970)

First, the[*decl-specifier-seq*](dcl.spec.general#nt:decl-specifier-seq "9.2.1 General [dcl.spec.general]") determines a type[.](#6.sentence-1)

In a declarationT D the[*decl-specifier-seq*](dcl.spec.general#nt:decl-specifier-seq "9.2.1 General [dcl.spec.general]")T determines the typeT[.](#6.sentence-2)

[*Example [4](#example-4)*:

In the declarationint unsigned i; the type specifiersintunsigned determine the type
“unsigned int” ([[dcl.type.simple]](dcl.type.simple "9.2.9.3 Simple type specifiers"))[.](#6.sentence-3)

— *end example*]

[7](#7)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L2995)

In a declaration[*attribute-specifier-seq*](dcl.attr.grammar#nt:attribute-specifier-seq "9.13.1 Attribute syntax and semantics [dcl.attr.grammar]")optTD whereD is an unadorned [*declarator-id*](dcl.decl.general#nt:declarator-id "9.3.1 General [dcl.decl.general]"),
the type of the declared entity is
“T”[.](#7.sentence-1)

[8](#8)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L3006)

In a declarationTD whereD has the form

( D1 )

the type of the contained[*declarator-id*](dcl.decl.general#nt:declarator-id "9.3.1 General [dcl.decl.general]") is the same as that of the contained[*declarator-id*](dcl.decl.general#nt:declarator-id "9.3.1 General [dcl.decl.general]") in the declarationT D1

Parentheses do not alter the type of the embedded[*declarator-id*](dcl.decl.general#nt:declarator-id "9.3.1 General [dcl.decl.general]"),
but they can alter the binding of complex declarators[.](#8.sentence-2)