信号量初始化失败，但返回的是RT_EOK

发布于 2021-10-19 10:20:06 浏览：1546 订阅该版

Papalymo 2021-10-19

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2 个回答

李肯陪你玩赚嵌入式 认证专家 2021-10-19

2022年度和2023年度RT-Thread社区优秀开源布道师，COC深圳城市开发者社区主理人，专注于嵌入式物联网的架构设计

或许你可以了解下rt_sem_init()和rt_sem_create()的区别。
```c
/**@{*/
/**
 * @brief    This function will initialize a static semaphore object.
 *
 * @note     For the static semaphore object, its memory space is allocated by the compiler during compiling,
 *           and shall placed on the read-write data segment or on the uninitialized data segment.
 *           By contrast, the rt_sem_create() function will allocate memory space automatically and initialize
 *           the semaphore.
 *
 * @see      rt_sem_create()
 *
 * @param    sem is a pointer to the semaphore to initialize. It is assumed that storage for the semaphore will be
 *           allocated in your application.
 *
 * @param    name is a pointer to the name you would like to give the semaphore.
 *
 * @param    value is the initial value for the semaphore.
 *           If used to share resources, you should initialize the value as the number of available resources.
 *           If used to signal the occurrence of an event, you should initialize the value as 0.
 *
 * @param    flag is the semaphore flag, which determines the queuing way of how multiple threads wait
 *           when the semaphore is not available.
 *           The semaphore flag can be ONE of the following values:
 *
 *               RT_IPC_FLAG_PRIO          The pending threads will queue in order of priority.
 *
 *               RT_IPC_FLAG_FIFO          The pending threads will queue in the first-in-first-out method
 *                                         (also known as first-come-first-served (FCFS) scheduling strategy).
 *
 *               NOTE: RT_IPC_FLAG_FIFO is a non-real-time scheduling mode. It is strongly recommended to
 *               use RT_IPC_FLAG_PRIO to ensure the thread is real-time UNLESS your applications concern about
 *               the first-in-first-out principle, and you clearly understand that all threads involved in
 *               this semaphore will become non-real-time threads.
 *
 * @return   Return the operation status. When the return value is RT_EOK, the initialization is successful.
 *           If the return value is any other values, it represents the initialization failed.
 *
 * @warning  This function can ONLY be called from threads.
 */
rt_err_t rt_sem_init(rt_sem_t    sem,
                     const char *name,
                     rt_uint32_t value,
                     rt_uint8_t  flag)
```
```c
/**
 * @brief    Creating a semaphore object.
 *
 * @note     For the semaphore object, its memory space is allocated automatically.
 *           By contrast, the rt_sem_init() function will initialize a static semaphore object.
 *
 * @see      rt_sem_init()
 *
 * @param    name is a pointer to the name you would like to give the semaphore.
 *
 * @param    value is the initial value for the semaphore.
 *           If used to share resources, you should initialize the value as the number of available resources.
 *           If used to signal the occurrence of an event, you should initialize the value as 0.
 *
 * @param    flag is the semaphore flag, which determines the queuing way of how multiple threads wait
 *           when the semaphore is not available.
 *           The semaphore flag can be ONE of the following values:
 *
 *               RT_IPC_FLAG_PRIO          The pending threads will queue in order of priority.
 *
 *               RT_IPC_FLAG_FIFO          The pending threads will queue in the first-in-first-out method
 *                                         (also known as first-come-first-served (FCFS) scheduling strategy).
 *
 *               NOTE: RT_IPC_FLAG_FIFO is a non-real-time scheduling mode. It is strongly recommended to
 *               use RT_IPC_FLAG_PRIO to ensure the thread is real-time UNLESS your applications concern about
 *               the first-in-first-out principle, and you clearly understand that all threads involved in
 *               this semaphore will become non-real-time threads.
 *
 * @return   Return a pointer to the semaphore object. When the return value is RT_NULL, it means the creation failed.
 *
 * @warning  This function can NOT be called in interrupt context. You can use macor RT_DEBUG_NOT_IN_INTERRUPT to check it.
 */
rt_sem_t rt_sem_create(const char *name, rt_uint32_t value, rt_uint8_t flag)
```