/* | |
* Amazon FreeRTOS POSIX V1.1.0 | |
* Copyright (C) 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved. | |
* | |
* Permission is hereby granted, free of charge, to any person obtaining a copy of | |
* this software and associated documentation files (the "Software"), to deal in | |
* the Software without restriction, including without limitation the rights to | |
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of | |
* the Software, and to permit persons to whom the Software is furnished to do so, | |
* subject to the following conditions: | |
* | |
* The above copyright notice and this permission notice shall be included in all | |
* copies or substantial portions of the Software. | |
* | |
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS | |
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR | |
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER | |
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN | |
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. | |
* | |
* http://aws.amazon.com/freertos | |
* http://www.FreeRTOS.org | |
*/ | |
/** | |
* @file semaphore.h | |
* @brief Semaphores. | |
* | |
* http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/semaphore.h.html | |
*/ | |
#ifndef _FREERTOS_POSIX_SEMAPHORE_H_ | |
#define _FREERTOS_POSIX_SEMAPHORE_H_ | |
/* FreeRTOS+POSIX includes. */ | |
#include "FreeRTOS_POSIX/time.h" | |
#include "FreeRTOS_POSIX_types.h" | |
/** | |
* @brief Semaphore type. | |
*/ | |
typedef PosixSemType_t sem_t; | |
/** | |
* @brief Destroy an unnamed semaphore. | |
* | |
* @see http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_destroy.html | |
* | |
* @retval 0 - upon successful completion | |
* | |
* @note Semaphore is destroyed regardless of whether there is any thread currently blocked on this semaphore. | |
*/ | |
int sem_destroy( sem_t * sem ); | |
/** | |
* @brief Get the value of a semaphore. | |
* | |
* @see http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_getvalue.html | |
* | |
* @retval 0 - Upon successful completion | |
* | |
* @note If sem is locked, then the object to which sval points is set to zero. | |
*/ | |
int sem_getvalue( sem_t * sem, | |
int * sval ); | |
/** | |
* @brief Initialize an unnamed semaphore. | |
* | |
* @see http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_init.html | |
* | |
* @note pshared is ignored. Semaphores will always be considered "shared". | |
* | |
* @retval 0 - upon successful completion | |
* @retval -1 - otherwise. System error variable errno is also set in this case. | |
* | |
* @sideeffect Possible errno values | |
* <br> | |
* EINVAL - The value argument exceeds {SEM_VALUE_MAX}. | |
* <br> | |
* ENOSPC - A resource required to initialize the semaphore has been exhausted. | |
*/ | |
int sem_init( sem_t * sem, | |
int pshared, | |
unsigned value ); | |
/** | |
* @brief Unlock a semaphore. | |
* | |
* @see http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_post.html | |
* | |
* @retval 0 - upon successful completion | |
*/ | |
int sem_post( sem_t * sem ); | |
/** | |
* @brief Lock a semaphore with timeout. | |
* | |
* @see http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_timedwait.html | |
* | |
* @retval 0 - upon successful completion | |
* @retval -1 - otherwise. System error variable errno is also set in this case. | |
* | |
* @sideeffect Possible errno values | |
* <br> | |
* EINVAL - parameter specified a nanoseconds field value less than zero or greater | |
* than or equal to 1000 million | |
* <br> | |
* ETIMEDOUT - The semaphore could not be locked before the specified timeout expired. | |
* | |
* @note Deadlock detection is not implemented. | |
*/ | |
int sem_timedwait( sem_t * sem, | |
const struct timespec * abstime ); | |
/** | |
* @brief Lock a semaphore if available. | |
* | |
* @see http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_trywait.html | |
* | |
* @retval 0 - upon successful completion | |
* @retval -1 - otherwise. System error variable errno is also set in this case. | |
* | |
* @sideeffect Possible errno values | |
* <br> | |
* EAGAIN - The semaphore was already locked, so it cannot be immediately locked by the sem_trywait() operation. | |
*/ | |
int sem_trywait( sem_t * sem ); | |
/** | |
* @brief Lock a semaphore. | |
* | |
* @see http://pubs.opengroup.org/onlinepubs/9699919799/functions/sem_wait.html | |
* | |
* @retval 0 - upon successful completion | |
* @retval -1 - otherwise. System error variable errno is also set in this case. | |
* | |
* @note Deadlock detection is not implemented. | |
*/ | |
int sem_wait( sem_t * sem ); | |
#endif /* ifndef _FREERTOS_POSIX_SEMAPHORE_H_ */ |