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.Dd September 2, 2012
.Dt CK_EPOCH_RECYCLE 3
.Sh NAME
.Nm ck_epoch_recycle
.Nd return an epoch record that may be used by caller
.Sh LIBRARY
Concurrency Kit (libck, \-lck)
.Sh SYNOPSIS
.In ck_epoch.h
.Ft ck_epoch_record_t *
.Fn ck_epoch_recycle "ck_epoch_t *epoch"
.Sh DESCRIPTION
The
.Fn ck_epoch_recycle 3
function attempts to return an unused epoch record object for use by
the caller. These epoch records were associated with previous calls
to the
.Fn ck_epoch_unregister 3
function.
.Sh EXAMPLE
.Bd -literal -offset indent
#include <ck_epoch.h>
#include <stdlib.h>

/*
 * epoch was previously initialized with ck_epoch_init.
 */
ck_epoch_t *epoch;

void
function(void)
{
	ck_epoch_record_t *record;

	record = ck_epoch_recycle(&epoch);
	if (record == NULL) {
		record = malloc(sizeof *record);
		if (record == NULL)
			return;

		ck_epoch_register(&epoch, record, NULL);
	}

	/*
	 * After we are done, we will unregister the record so it
	 * can be used by other new participants in the epoch system
	 * provided by the object pointed to by "epoch".
	 */
	ck_epoch_unregister(&epoch, record);
	return;
}
.Ed
.Sh RETURN VALUES
This function returns a pointer to a
.Dv ck_epoch_record_t
object. If no unused record was found to be associated with the
object pointed to by
.Fa epoch ,
then the function will return NULL.
.Sh ERRORS
Behavior is undefined if the object pointed to by
.Fa epoch
is not a valid epoch object.
.Sh SEE ALSO
.Xr ck_epoch_init 3 ,
.Xr ck_epoch_register 3 ,
.Xr ck_epoch_unregister 3 ,
.Xr ck_epoch_poll 3 ,
.Xr ck_epoch_synchronize 3 ,
.Xr ck_epoch_reclaim 3 ,
.Xr ck_epoch_barrier 3 ,
.Xr ck_epoch_call 3 ,
.Xr ck_epoch_begin 3 ,
.Xr ck_epoch_end 3
.Pp
Additional information available at http://concurrencykit.org/