forked from Qortal/Brooklyn
114 lines
3.7 KiB
C
114 lines
3.7 KiB
C
/*
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Copyright (c) 2012, Broadcom Europe Ltd
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of the copyright holder nor the
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names of its contributors may be used to endorse or promote products
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derived from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*=============================================================================
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VideoCore OS Abstraction Layer - named semaphores
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=============================================================================*/
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#ifndef VCOS_NAMED_SEMAPHORE_H
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#define VCOS_NAMED_SEMAPHORE_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include "interface/vcos/vcos_types.h"
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#include "vcos.h"
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/**
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* \file
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*
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* Create a named semaphore, or open an existing one by name.
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*
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*/
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/**
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* \brief Create a named semaphore.
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*
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* Semaphores are not re-entrant.
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*
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* @param sem Pointer to memory to be initialized
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* @param name A name for this semaphore.
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* @param count The initial count for the semaphore.
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*
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* @return VCOS_SUCCESS if the semaphore was created.
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*
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*/
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VCOS_INLINE_DECL
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VCOS_STATUS_T vcos_named_semaphore_create(VCOS_NAMED_SEMAPHORE_T *sem, const char *name, VCOS_UNSIGNED count);
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/**
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* \brief Wait on a named semaphore.
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*
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* There is no timeout option on a semaphore, as adding this will slow down
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* implementations on some platforms. If you need that kind of behaviour, use
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* an event group.
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*
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* This always returns VCOS_SUCCESS and so should really be a void function. However
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* too many lines of code would need to be changed in non-trivial ways, so for now
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* it is non-void.
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*
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* @param sem Semaphore to wait on
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* @return VCOS_SUCCESS - semaphore was taken.
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*
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*/
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VCOS_INLINE_DECL
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void vcos_named_semaphore_wait(VCOS_NAMED_SEMAPHORE_T *sem);
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/**
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* \brief Try to wait for a semaphore.
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*
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* Try to obtain the semaphore. If it is already taken, return VCOS_TIMEOUT.
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* @param sem Semaphore to wait on
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* @return VCOS_SUCCESS - semaphore was taken.
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* VCOS_EAGAIN - could not take semaphore
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*/
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VCOS_INLINE_DECL
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VCOS_STATUS_T vcos_named_semaphore_trywait(VCOS_NAMED_SEMAPHORE_T *sem);
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/**
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* \brief Post a semaphore.
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*
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* @param sem Semaphore to wait on
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*/
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VCOS_INLINE_DECL
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void vcos_named_semaphore_post(VCOS_NAMED_SEMAPHORE_T *sem);
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/**
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* \brief Delete a semaphore, releasing any resources consumed by it.
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*
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* @param sem Semaphore to wait on
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*/
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void vcos_named_semaphore_delete(VCOS_NAMED_SEMAPHORE_T *sem);
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#ifdef __cplusplus
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}
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#endif
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#endif
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