MEMBAR_OPS(3)

MEMBAR_OPS(3) | Library Functions Manual | MEMBAR_OPS(3)

# NAME

membar_ops, membar_enter, membar_exit, membar_producer, membar_consumer, membar_sync — memory access barrier operations

# SYNOPSIS

#include <sys/atomic.h>

void
membar_enter(void);

void
membar_exit(void);

void
membar_producer(void);

void
membar_consumer(void);

void
membar_sync(void);

# DESCRIPTION

The membar_ops family of functions provide memory access barrier operations necessary for synchronization in multiprocessor execution environments that have relaxed load and store order.

membar_enter()
  Any store preceding membar_enter() will reach global visibility before all loads and stores following it.

  membar_enter() is typically used in code that implements locking primitives to ensure that a lock protects its data.

membar_exit()
  All loads and stores preceding membar_exit() will reach global visibility before any store that follows it.

  membar_exit() is typically used in code that implements locking primitives to ensure that a lock protects its data.

membar_producer()
  All stores preceding the memory barrier will reach global visibility before any stores after the memory barrier reach global visibility.
membar_consumer()
  All loads preceding the memory barrier will complete before any loads after the memory barrier complete.
membar_sync()
  All loads and stores preceding the memory barrier will complete and reach global visibility before any loads and stores after the memory barrier complete and reach global visibility.

# SEE ALSO

atomic_ops(3)

# HISTORY

The membar_ops functions first appeared in NetBSD 5.0.

February 11, 2007 | NetBSD 5.99