| Skip Navigation Links | |
| Exit Print View | |
 | man pages section 3: Basic Library Functions Oracle Solaris 11 Information Library |
| Skip Navigation Links | |
| Exit Print View | |
| man pages section 3: Basic Library Functions Oracle Solaris 11 Information Library |
enable_extended_FILE_stdio(3C)
posix_spawnattr_getschedparam(3C)
posix_spawnattr_getschedpolicy(3C)
posix_spawnattr_getsigdefault(3C)
posix_spawnattr_getsigignore_np(3C)
posix_spawnattr_getsigmask(3C)
posix_spawnattr_setschedparam(3C)
posix_spawnattr_setschedpolicy(3C)
posix_spawnattr_setsigdefault(3C)
posix_spawnattr_setsigignore_np(3C)
posix_spawnattr_setsigmask(3C)
posix_spawn_file_actions_addclose(3C)
posix_spawn_file_actions_addclosefrom_np(3C)
posix_spawn_file_actions_adddup2(3C)
posix_spawn_file_actions_addopen(3C)
posix_spawn_file_actions_destroy(3C)
posix_spawn_file_actions_init(3C)
pthread_attr_getdetachstate(3C)
pthread_attr_getinheritsched(3C)
pthread_attr_getschedparam(3C)
pthread_attr_getschedpolicy(3C)
pthread_attr_setdetachstate(3C)
pthread_attr_setinheritsched(3C)
pthread_attr_setschedparam(3C)
pthread_attr_setschedpolicy(3C)
pthread_barrierattr_destroy(3C)
pthread_barrierattr_getpshared(3C)
pthread_barrierattr_setpshared(3C)
pthread_condattr_getpshared(3C)
pthread_condattr_setpshared(3C)
pthread_cond_reltimedwait_np(3C)
pthread_key_create_once_np(3C)
pthread_mutexattr_getprioceiling(3C)
pthread_mutexattr_getprotocol(3C)
pthread_mutexattr_getpshared(3C)
pthread_mutexattr_getrobust(3C)
pthread_mutexattr_setprioceiling(3C)
pthread_mutexattr_setprotocol(3C)
pthread_mutexattr_setpshared(3C)
pthread_mutexattr_setrobust(3C)
pthread_mutex_getprioceiling(3C)
pthread_mutex_reltimedlock_np(3C)
pthread_mutex_setprioceiling(3C)
pthread_rwlockattr_destroy(3C)
pthread_rwlockattr_getpshared(3C)
pthread_rwlockattr_setpshared(3C)
pthread_rwlock_reltimedrdlock_np(3C)
pthread_rwlock_reltimedwrlock_np(3C)
pthread_rwlock_timedrdlock(3C)
pthread_rwlock_timedwrlock(3C)
rctlblk_get_enforced_value(3C)
- multiple readers, single writer locks
cc –mt [flag... ]file...[library... ]#include <synch.h>intrwlock_init(rwlock_t *rwlp,inttype,void *arg);
intrwlock_destroy(rwlock_t *rwlp);
intrw_rdlock(rwlock_t *rwlp);
intrw_wrlock(rwlock_t *rwlp);
intrw_unlock(rwlock_t *rwlp);
intrw_tryrdlock(rwlock_t *rwlp);
intrw_trywrlock(rwlock_t *rwlp);
Many threads can have simultaneous read-only access to data, while only onethread can have write access at any given time. Multiple read accesswith single write access is controlled by locks, which are generally usedto protect data that is frequently searched.
Readers/writer locks can synchronize threads in this process and other processes ifthey are allocated in writable memory and shared among cooperating processes(seemmap(2)), and are initialized for this purpose.
Additionally, readers/writer locks must be initialized prior to use.rwlock_init() The readers/writerlock pointed to byrwlp is initialized byrwlock_init(). A readers/writerlock is capable of having several types of behavior, which is specified bytype.arg is currently not used, although a future type may define new behavior parameters by way ofarg.
Thetype argument can be one of the following:
The readers/writer lock can synchronize threads in this process and other processes. The readers/writer lock should be initialized by only one process.arg is ignored. A readers/writer lock initialized with this type, must be allocated in memory shared between processes, either in Sys V shared memory (seeshmop(2)) or in memory mapped to a file (seemmap(2)). It is illegal to initialize the object this way and to not allocate it in such shared memory.
The readers/writer lock can synchronize threads in this process, only.arg is ignored.
Additionally, readers/writer locks can be initialized by allocation in zeroed memory.Atype ofUSYNC_THREAD is assumed in this case. Multiple threads mustnot simultaneously initialize the same readers/writer lock. And a readers/writer lockmust not be re-initialized while in use by other threads.
The following are default readers/writer lock initialization (intra-process):
rwlock_t rwlp;rwlock_init(&rwlp, NULL, NULL);
or
rwlock_init(&rwlp, USYNC_THREAD, NULL);
or
rwlock_t rwlp = DEFAULTRWLOCK;
The following is a customized readers/writer lock initialization (inter-process):
rwlock_init(&rwlp, USYNC_PROCESS, NULL);
Any state associated with the readers/writer lock pointed to byrwlp aredestroyed byrwlock_destroy() and the readers/writer lock storage space is notreleased.
rw_rdlock() gets a read lock on the readers/writer lock pointed to byrwlp. If the readers/writer lock is currently locked for writing, the callingthread blocks until the write lock is freed. Multiple threads may simultaneouslyhold a read lock on a readers/writer lock.
rw_tryrdlock() trys to get a read lock on the readers/writer lock pointedto byrwlp. If the readers/writer lock is locked for writing, itreturns an error; otherwise, the read lock is acquired.
rw_wrlock() gets a write lock on the readers/writer lock pointed to byrwlp. If the readers/writer lock is currently locked for reading or writing,the calling thread blocks until all the read and write locks arefreed. At any given time, only one thread may have a write lockon a readers/writer lock.
rw_trywrlock() trys to get a write lock on the readers/writer lock pointedto byrwlp. If the readers/writer lock is currently locked for readingor writing, it returns an error.
rw_unlock() unlocks a readers/writer lock pointed to byrwlp, if thereaders/writer lock is locked and the calling thread holds the lock foreither reading or writing. One of the other threads that is waitingfor the readers/writer lock to be freed will be unblocked, provided thereis other waiting threads. If the calling thread does not hold thelock for either reading or writing, no error status is returned, andthe program's behavior is unknown.
If successful, these functions return0. Otherwise, a non-zero value is returnedto indicate the error.
Therwlock_init() function will fail if:
type is invalid.
Therw_tryrdlock() orrw_trywrlock() functions will fail if:
The reader or writer lock pointed to byrwlp was already locked.
These functions may fail if:
rwlp orarg points to an illegal address.
Seeattributes(5) for descriptions of the following attributes:
|
These interfaces also available by way of:
#include<thread.h>
If multiple threads are waiting for a readers/writer lock, the acquisition orderis random by default. However, some implementations may bias acquisition order toavoid depriving writers. The current implementation favors writers over readers.
Copyright © 2011, Oracle and/or its affiliates. All rights reserved.Legal Notices |   |