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

# ck\_hs\_apply(3)

apply a function to hash set value

## NAME

**ck\_hs\_apply** – apply a function to hash set value

## LIBRARY

Concurrency Kit (libck, -lck)

## SYNOPSIS

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

*void* *\**\

**ck\_hs\_apply\_fn\_t**(*void \*key*, *void \*closure*);

*bool*\

**ck\_hs\_apply**(*ck\_hs\_t \*hs*, *unsigned long hash*, *const void \*key*, *ck\_hs\_apply\_fn\_t \*function*, *void \*argument*);

## DESCRIPTION

The **ck\_hs\_apply**(*3*) function will lookup the hash set slot associated with *key* and pass it to function pointed to by *function* for further action. This callback may remove or replace the value by respectively returning NULL or a pointer to another object with an identical key. The first argument passed to *function* is a pointer to the object found in the hash set and the second argument is the *argument* pointer passed to **ck\_hs\_apply**(*3*). If the pointer returned by *function* is equivalent to the first argument then no modification is made to the hash set.

## RETURN VALUES

Upon successful completion, **ck\_hs\_apply**(*3*) returns true and otherwise returns false on failure.

## SEE ALSO

[ck\_hs\_init(3)](/ck_hs_init/3.md), [ck\_hs\_move(3)](/ck_hs_move/3.md), [ck\_hs\_destroy(3)](/ck_hs_destroy/3.md), [ck\_hs\_fas(3)](/ck_hs_fas/3.md), [CK\_HS\_HASH(3)](/CK_HS_HASH/3.md), [ck\_hs\_iterator\_init(3)](/ck_hs_iterator_init/3.md), [ck\_hs\_next(3)](/ck_hs_next/3.md), [ck\_hs\_get(3)](/ck_hs_get/3.md), [ck\_hs\_put(3)](/ck_hs_put/3.md), [ck\_hs\_put\_unique(3)](/ck_hs_put_unique/3.md), [ck\_hs\_remove(3)](/ck_hs_remove/3.md), [ck\_hs\_grow(3)](/ck_hs_grow/3.md), [ck\_hs\_rebuild(3)](/ck_hs_rebuild/3.md), [ck\_hs\_gc(3)](/ck_hs_gc/3.md), [ck\_hs\_count(3)](/ck_hs_count/3.md), [ck\_hs\_reset(3)](/ck_hs_reset/3.md), [ck\_hs\_reset\_size(3)](/ck_hs_reset_size/3.md), [ck\_hs\_stat(3)](/ck_hs_stat/3.md)

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