ck_epoch_barrier(3)
block until a grace period and all callbacks have been dispatched
LIBRARY
Concurrency Kit (libck, -lck)
SYNOPSIS
In ck_epoch.h
Ft void
Fn ck_epoch_barrier ck_epoch_t *epoch ck_epoch_record_t *record
DESCRIPTION
The
Fn ck_epoch_barrier 3
function will block the caller until a grace period has been
detected, according to the semantics of epoch reclamation.
Any objects requiring safe memory reclamation which are logically
deleted are safe for physical deletion following a call to
Fn ck_epoch_barrier 3 . This function will also dispatch all callbacks
associated with
Fa epoch
that were previously scheduled via
Fn ck_epoch_call 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);
/*
* 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(epoch, record);
/* Logically delete an object. */
s = ck_stack_pop_upmc(stack);
ck_epoch_end(epoch, 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_barrier(epoch, record);
/* It is now safe to physically delete the object. */
free(s);
return;
}
RETURN VALUES
This function has no return value.
ERRORS
Behavior is undefined if the object pointed to by
Fa epoch
is not a valid epoch object. The object pointed to by
Fa record
must have been previously registered via
Fn ck_epoch_register 3 .