forked from acouzens/open5gs
111 lines
3.4 KiB
C
111 lines
3.4 KiB
C
#ifndef __CORE_RWLOCK_H__
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#define __CORE_RWLOCK_H__
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/**
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* @file rwlock.h
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* @brief CORE Reader/Writer Lock Routines
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*/
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#include "core.h"
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#include "core_errno.h"
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#ifdef __cplusplus
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extern "C" {
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#endif /* __cplusplus */
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/**
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* @defgroup rwlock Reader/Writer Lock Routines
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* @ingroup CORE
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* @{
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*/
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/** Opaque read-write thread-safe lock. */
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typedef c_uintptr_t rwlock_id;
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/**
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* Initialize Read-Write Lock Pool
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*/
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CORE_DECLARE(status_t) rwlock_init(void);
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/**
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* Finalize Read-Write Lock Pool
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*/
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CORE_DECLARE(status_t) rwlock_final(void);
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/**
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* Note: The following operations have undefined results: unlocking a
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* read-write lock which is not locked in the calling thread; write
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* locking a read-write lock which is already locked by the calling
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* thread; destroying a read-write lock more than once; clearing or
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* destroying the pool from which a <b>locked</b> read-write lock is
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* allocated.
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*/
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/**
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* Create and initialize a read-write lock that can be used to synchronize
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* threads.
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* @param id the memory address where the newly created readwrite lock
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* will be stored.
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*/
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CORE_DECLARE(status_t) rwlock_create(rwlock_id *id);
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/**
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* Acquire a shared-read lock on the given read-write lock. This will allow
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* multiple threads to enter the same critical section while they have acquired
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* the read lock.
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* @param id the read-write lock on which to acquire the shared read.
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*/
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CORE_DECLARE(status_t) rwlock_rdlock(rwlock_id id);
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/**
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* Attempt to acquire the shared-read lock on the given read-write lock. This
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* is the same as rwlock_rdlock(), only that the function fails
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* if there is another thread holding the write lock, or if there are any
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* write threads blocking on the lock. If the function fails for this case,
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* CORE_EBUSY will be returned. Note: it is important that the
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* CORE_STATUS_IS_EBUSY(s) macro be used to determine if the return value was
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* CORE_EBUSY, for portability reasons.
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* @param id the rwlock on which to attempt the shared read.
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*/
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CORE_DECLARE(status_t) rwlock_tryrdlock(rwlock_id id);
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/**
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* Acquire an exclusive-write lock on the given read-write lock. This will
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* allow only one single thread to enter the critical sections. If there
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* are any threads currently holding the read-lock, this thread is put to
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* sleep until it can have exclusive access to the lock.
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* @param id the read-write lock on which to acquire the exclusive write.
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*/
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CORE_DECLARE(status_t) rwlock_wrlock(rwlock_id id);
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/**
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* Attempt to acquire the exclusive-write lock on the given read-write lock.
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* This is the same as rwlock_wrlock(), only that the function fails
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* if there is any other thread holding the lock (for reading or writing),
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* in which case the function will return CORE_EBUSY. Note: it is important
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* that the CORE_STATUS_IS_EBUSY(s) macro be used to determine if the return
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* value was CORE_EBUSY, for portability reasons.
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* @param id the rwlock on which to attempt the exclusive write.
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*/
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CORE_DECLARE(status_t) rwlock_trywrlock(rwlock_id id);
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/**
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* Release either the read or write lock currently held by the calling thread
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* associated with the given read-write lock.
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* @param id the read-write lock to be released (unlocked).
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*/
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CORE_DECLARE(status_t) rwlock_unlock(rwlock_id id);
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/**
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* Destroy the read-write lock and free the associated memory.
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* @param id the rwlock to destroy.
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*/
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CORE_DECLARE(status_t) rwlock_delete(rwlock_id id);
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/** @} */
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#ifdef __cplusplus
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}
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#endif /* __cplusplus */
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#endif /* ! __CORE_RWLOCK_H__ */
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