[dcl.constinit]

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

## 9.2 Specifiers [[dcl.spec]](dcl.spec#dcl.constinit)

### 9.2.7 The constinit specifier [dcl.constinit]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L1056)

The constinit specifier shall be applied only
to a declaration of a variable with static or thread storage duration
or to a structured binding declaration ([[dcl.struct.bind]](dcl.struct.bind "9.7 Structured binding declarations"))[.](#1.sentence-1)

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

A structured binding declaration introduces a uniquely named variable,
to which the constinit specifier applies[.](#1.sentence-2)

— *end note*]

If the specifier is applied to any declaration of a variable,
it shall be applied to the initializing declaration[.](#1.sentence-3)

No diagnostic is required if no constinit declaration
is reachable at the point of the initializing declaration[.](#1.sentence-4)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L1069)

If a variable declared with the constinit specifier has
dynamic initialization ([[basic.start.dynamic]](basic.start.dynamic "6.10.3.3 Dynamic initialization of non-block variables")), the program is ill-formed,
even if the implementation would perform that initialization as
a static initialization ([[basic.start.static]](basic.start.static "6.10.3.2 Static initialization"))[.](#2.sentence-1)

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

The constinit specifier ensures that the variable
is initialized during static initialization[.](#2.sentence-2)

— *end note*]

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/declarations.tex#L1079)

[*Example [1](#example-1)*: const char * g() { return "dynamic initialization"; }constexpr const char * f(bool p) { return p ? "constant initializer" : g(); }constinit const char * c = f(true); // OKconstinit const char * d = f(false); // error — *end example*]