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CK_EPOCH_BARRIER(3)   DragonFly Library Functions Manual   CK_EPOCH_BARRIER(3)

NAME
     ck_epoch_barrier - block until a grace period and all callbacks have been
     dispatched

LIBRARY
     Concurrency Kit (libck, -lck)

SYNOPSIS
     #include <ck_epoch.h>

     void
     ck_epoch_barrier(ck_epoch_record_t *record);

DESCRIPTION
     The 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
     ck_epoch_barrier(3). This function will also dispatch all callbacks
     associated with epoch that were previously scheduled via
     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(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_barrier(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 epoch is not a valid
     epoch object. The object pointed to by 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_synchronize(3),
     ck_epoch_reclaim(3), ck_epoch_call(3), ck_epoch_begin(3), ck_epoch_end(3)

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

                               September 2, 2012