---
name: "__gnu_pbds::null_type"
section: "3"
platform: "linux"
package: "gcc"
version: "16.2.1+r23+gd564253eb6c8-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/__gnu_pbds::null_type"
---

# \_\_gnu\_pbds::null\_type(3)

Represents no type, or absence of type, for template tricks.

## NAME

\_\_gnu\_pbds::null\_type - Represents no type, or absence of type, for template tricks.

## SYNOPSIS

\#include \<tag\_and\_trait.hpp\>

Inherited by **\_\_gnu\_pbds::null\_node\_update\< node\_const\_iterator, node\_iterator, Cmp\_Fn, \_Alloc \> \***, **\_\_gnu\_pbds::null\_node\_update\< node\_const\_iterator, node\_iterator, \_ATraits, \_Alloc \> \***, **\_\_gnu\_pbds::null\_node\_update\< node\_const\_iterator, node\_const\_iterator, \_ATraits, \_Alloc \> \***, **\_\_gnu\_pbds::null\_node\_update\< \_\_it\_type, \_\_it\_type, Cmp\_Fn, \_Alloc \>**, and **\_\_gnu\_pbds::null\_node\_update\< \_Tp1, \_Tp2, \_Tp3, \_Tp4 \>**.

## Detailed Description

Represents no type, or absence of type, for template tricks.

In a mapped-policy, indicates that an associative container is a set.

In a list-update policy, indicates that each link does not need metadata.

In a hash policy, indicates that the combining hash function is actually a ranged hash function.

In a probe policy, indicates that the combining probe function is actually a ranged probe function.

## Author

Generated automatically by Doxygen for libstdc++ from the source code.