[support.types.nullptr]

# 17 Language support library [[support]](./#support)

## 17.2 Common definitions [[support.types]](support.types#nullptr)

### 17.2.3 Null pointers [support.types.nullptr]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/support.tex#L262)

The type nullptr_t is a synonym
for the type of a nullptr expression, and it
has the characteristics
described in [[basic.fundamental]](basic.fundamental "6.9.2 Fundamental types") and [[conv.ptr]](conv.ptr "7.3.12 Pointer conversions")[.](#1.sentence-1)

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

Although nullptr's address cannot be taken, the address of anothernullptr_t object that is an lvalue can be taken[.](#1.sentence-2)

â *end note*]

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/support.tex#L273)

The macroNULL is an implementation-defined null pointer constant[.](#2.sentence-1)[159](#footnote-159 "Possible definitions include 0 and 0L, but not (void*)0.")

See also: ISO/IEC 9899:2024, 7.22

[159)](#footnote-159)[159)](#footnoteref-159)

Possible definitions include0 and0L,
but not(void*)0[.](#footnote-159.sentence-1)
