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ck/doc/ck_epoch_synchronize

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.Dd September 2, 2012
.Dt CK_EPOCH_SYNCHRONIZE 3
.Sh NAME
.Nm ck_epoch_synchronize
.Nd block until a grace period has been detected
.Sh LIBRARY
Concurrency Kit (libck, \-lck)
.Sh SYNOPSIS
.In ck_epoch.h
.Ft void
.Fn ck_epoch_synchronize "ck_epoch_record_t *record"
.Sh DESCRIPTION
The
.Fn 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
.Fn ck_epoch_synchronize 3 .
If you require that all callbacks be dispatched, then it is suggested
that you use
.Fn ck_epoch_barrier 3
instead or follow a call of
.Fn ck_epoch_synchronize 3
with
.Fn ck_epoch_reclaim 3 .
.Sh EXAMPLE
.Bd -literal -offset indent
#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(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;
}
.Ed
.Sh RETURN VALUES
This function has no return value.
.Sh ERRORS
The object pointed to by .Fa record must have been previously registered via
.Fn ck_epoch_register 3 .
.Sh SEE ALSO
.Xr ck_epoch_init 3 ,
.Xr ck_epoch_register 3 ,
.Xr ck_epoch_unregister 3 ,
.Xr ck_epoch_recycle 3 ,
.Xr ck_epoch_poll 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/