1. Manuals
  2. Tumbleweed
  3. ck-devel
  4. ck_epoch_synchronize(3)

Scroll to navigation

CK_EPOCH_SYNCHRONIZE(3) Library Functions Manual CK_EPOCH_SYNCHRONIZE(3)

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 (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 (3) instead or follow a call of ck_epoch_synchronize(3) with (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_register(3), ck_epoch_unregister(3), ck_epoch_recycle(3), ck_epoch_poll(3), ck_epoch_reclaim(3), ck_epoch_barrier(3), ck_epoch_call(3), ck_epoch_begin(3), ck_epoch_end(3)

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

September 2, 2012