---
name: "ck_pr_btr"
section: "3"
platform: "linux"
package: "libck-dev"
version: "0.7.2-6"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/ck_pr_btr"
---

# ck\_pr\_btr(3)

atomic bit test-and-reset operations

## NAME

**ck\_pr\_btr\_ptr**, **ck\_pr\_btr\_uint**, **ck\_pr\_btr\_int**, **ck\_pr\_btr\_64**, **ck\_pr\_btr\_32**, **ck\_pr\_btr\_16** – atomic bit test-and-reset operations

## LIBRARY

Concurrency Kit (libck, -lck)

## SYNOPSIS

**#include \<ck\_pr.h\>**

*bool*\

**ck\_pr\_btr\_ptr**(*void \*target*, *unsigned int bit\_index*);

*bool*\

**ck\_pr\_btr\_uint**(*uint \*target*, *unsigned int bit\_index*);

*bool*\

**ck\_pr\_btr\_int**(*int \*target*, *unsigned int bit\_index*);

*bool*\

**ck\_pr\_btr\_64**(*uint64\_t \*target*, *unsigned int bit\_index*);

*bool*\

**ck\_pr\_btr\_32**(*uint32\_t \*target*, *unsigned int bit\_index*);

*bool*\

**ck\_pr\_btr\_16**(*uint16\_t \*target*, *unsigned int bit\_index*);

## DESCRIPTION

The **ck\_pr\_btr**(*3*) family of functions atomically fetch the value of the bit in *target* at index *bit\_index* and set that bit to 0.

## RETURN VALUES

This family of functions returns the original value of the bit at offset *bit\_index* that is in the value pointed to by *target*.

## SEE ALSO

[ck\_pr\_fence\_load(3)](/ck_pr_fence_load/3.md), [ck\_pr\_fence\_load\_depends(3)](/ck_pr_fence_load_depends/3.md), [ck\_pr\_fence\_store(3)](/ck_pr_fence_store/3.md), [ck\_pr\_fence\_memory(3)](/ck_pr_fence_memory/3.md), [ck\_pr\_load(3)](/ck_pr_load/3.md), [ck\_pr\_store(3)](/ck_pr_store/3.md), [ck\_pr\_fas(3)](/ck_pr_fas/3.md), [ck\_pr\_faa(3)](/ck_pr_faa/3.md), [ck\_pr\_inc(3)](/ck_pr_inc/3.md), [ck\_pr\_dec(3)](/ck_pr_dec/3.md), [ck\_pr\_neg(3)](/ck_pr_neg/3.md), [ck\_pr\_not(3)](/ck_pr_not/3.md), [ck\_pr\_sub(3)](/ck_pr_sub/3.md), [ck\_pr\_and(3)](/ck_pr_and/3.md), [ck\_pr\_or(3)](/ck_pr_or/3.md), [ck\_pr\_xor(3)](/ck_pr_xor/3.md), [ck\_pr\_add(3)](/ck_pr_add/3.md), [ck\_pr\_btc(3)](/ck_pr_btc/3.md), [ck\_pr\_bts(3)](/ck_pr_bts/3.md), [ck\_pr\_cas(3)](/ck_pr_cas/3.md)

Additional information available at http://concurrencykit.org/