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

# ck\_epoch\_synchronize(3)

block until a grace period has been detected

## NAME

**ck\_epoch\_synchronize** – block until a grace period has been detected

## LIBRARY

Concurrency Kit (libck, -lck)

## SYNOPSIS

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

*void*\

**ck\_epoch\_synchronize**(*ck\_epoch\_record\_t \*record*);

## DESCRIPTION

The **ck\_epoch\_synchronize**(*3*) function will block the caller until a grace period has been detected, according to the semantics of epoch reclamation. It is not safe to call this function on a record that is in an active section. Any objects requiring safe memory reclamation which are logically deleted are safe for physical deletion following a call to **ck\_epoch\_synchronize**(*3*). If you require that all callbacks be dispatched, then it is suggested that you use **ck\_epoch\_barrier**(*3*) instead or follow a call of **ck\_epoch\_synchronize**(*3*) with **ck\_epoch\_reclaim**(*3*).

## EXAMPLE

```
#include <ck_epoch.h>
#include <ck_stack.h>
#include <stdlib.h>
/*
 * epoch was previously initialized with ck_epoch_init.
 * stack was previously initialized with ck_stack_init.
 */
ck_epoch_t *epoch;
ck_stack_t *stack;
void
function(void)
{
	ck_epoch_record_t *record;
	ck_stack_entry_t *s;
	record = malloc(sizeof *record);
	ck_epoch_register(&epoch, record, NULL);
	/*
	 * We are using an epoch section here to guarantee no
	 * nodes in the stack are deleted while we are dereferencing
	 * them. This is needed here because there are multiple writers.
	 * If there was only one thread popping from the this stack,
	 * then there is no need to ck_epoch_begin/ck_epoch_end.
	 */
	ck_epoch_begin(record);
	/* Logically delete an object. */
	s = ck_stack_pop_upmc(stack);
	ck_epoch_end(record);
	/*
	 * Wait until no threads could possibly have a reference to the
	 * object we just popped (assume all threads are simply executing
	 * ck_stack_pop_upmc).
	 */
	ck_epoch_synchronize(record);
	/* It is now safe to physically delete the object. */
	free(s);
	return;
}
```

## RETURN VALUES

This function has no return value.

## ERRORS

The object pointed to by .Fa record must have been previously registered via **ck\_epoch\_register**(*3*).

## SEE ALSO

[ck\_epoch\_init(3)](/ck_epoch_init/3.md), [ck\_epoch\_register(3)](/ck_epoch_register/3.md), [ck\_epoch\_unregister(3)](/ck_epoch_unregister/3.md), [ck\_epoch\_recycle(3)](/ck_epoch_recycle/3.md), [ck\_epoch\_poll(3)](/ck_epoch_poll/3.md), [ck\_epoch\_reclaim(3)](/ck_epoch_reclaim/3.md), [ck\_epoch\_barrier(3)](/ck_epoch_barrier/3.md), [ck\_epoch\_call(3)](/ck_epoch_call/3.md), [ck\_epoch\_begin(3)](/ck_epoch_begin/3.md), [ck\_epoch\_end(3)](/ck_epoch_end/3.md)

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