Man page - ck_swlock(3)

Packages contains this manual

Manual


NAME

ck_swlock_init, ck_swlock_write_latch, ck_swlock_write_unlatch, ck_swlock_write_lock, ck_swlock_write_unlock, ck_swlock_write_trylock, ck_swlock_write_downgrade, ck_swlock_locked_writer, ck_swlock_read_lock, ck_swlock_read_trylock, ck_swlock_read_unlock, ck_swlock_locked_reader — centralized copy-safe write-biased single-writer read-write locks

LIBRARY

Concurrency Kit (libck, -lck)

SYNOPSIS

#include <ck_swlock.h>

ck_swlock_t lock = CK_SWLOCK_INITIALIZER;

void

ck_swlock_init ( ck_swlock_t *lock );

void

ck_swlock_write_lock ( ck_swlock_t *lock );

void

ck_swlock_write_unlock ( ck_swlock_t *lock );

void

ck_swlatch_write_latch ( ck_swlatch_t *latch );

void

ck_swlatch_write_unlatch ( ck_swlatch_t *latch );

bool

ck_swlock_write_trylock ( ck_swlock_t *lock );

bool

ck_swlock_write_downgrade ( ck_swlock_t *lock );

bool

ck_swlock_locked_writer ( ck_swlock_t *lock );

void

ck_swlock_read_lock ( ck_swlock_t *lock );

bool

ck_swlock_read_trylock ( ck_swlock_t *lock );

void

ck_swlock_read_unlock ( ck_swlock_t *lock );

bool

ck_swlock_locked_reader ( ck_swlock_t *lock );

DESCRIPTION

This is a centralized write-biased single-writer reader-writer lock. It requires half the space that ck_rwlock does and has a low latency fast path. The lock supports latch and unlatch operations that allow it to be used in a copy-safe manner (reader-bits may be over-written safely).

EXAMPLE

#include <ck_swlock.h>

static ck_swlock_t lock = CK_SWLOCK_INITIALIZER;

static void
reader(void)
{

for (;;) {

ck_swlock_read_lock(&lock);

/* Read-side critical section. */

ck_swlock_read_unlock(&lock);

if (ck_swlock_read_trylock(&lock) == true) {

/* Read-side critical section. */

ck_swlock_read_unlock(&lock);

}

}

return;

}

static void
writer(void)
{

ck_swlock_t contrived;

for (;;) {

ck_swlock_write_lock(&lock);

/* Write-side critical section. */

ck_swlock_write_unlock(&lock);

if (ck_swlock_write_trylock(&lock) == true) {

/* Write-side critical section. */

ck_swlock_write_unlock(&lock);

}

ck_swlock_write_latch(&lock);

/* Write-side critical section. */

/* This is safe to do with-in a latch. */

contrived = lock;

lock = contrived;

ck_swlock_write_unlatch(&lock);

}

return;

}

SEE ALSO

ck_brlock (3), ck_elide (3), ck_pflock (3), ck_rwlock (3), ck_tflock (3)

Additional information available at http://concurrencykit.org/ April 22, 2014. ck_swlock (3)