AMiRo-OS

/*

µRtWare is a lightweight publish/subscribe middleware for real-time

applications. It was developed as part of the software habitat for the

Autonomous Mini Robot [1] (AMiRo) but can be used for other purposes as well.

Copyright (C) 2018..2020  Thomas Schöpping et al.

This program is free software: you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation, either version 3 of the License, or

(at your option) any later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program.  If not, see <http://www.gnu.org/licenses/>.

*/

#ifndef URT_OSAL_H

#define URT_OSAL_H

#include <urtware.h>

/*============================================================================*/

/* VERSION                                                                    */

/*============================================================================*/

/**

 * @brief   The µRtWare operating system abstraction layer interface major version.

 * @note    Changes of the major version imply incompatibilities.

 */

#define URT_OSAL_VERSION_MAJOR                  0

/**

 * @brief   The µRtWare operating system abstraction layer interface minor version.

 * @note    A higher minor version implies new functionalty, but all old interfaces are still available.

 */

#define URT_OSAL_VERSION_MINOR                  1

/*============================================================================*/

/* DEPENDENCIES                                                               */

/*============================================================================*/

#include <stdint.h>

/*============================================================================*/

/* DEBUG                                                                      */

/*============================================================================*/

#if defined(__cplusplus)

extern "C" {

#endif /* defined(__cplusplus) */

#if !defined(urtDebugAssert) || defined(__DOXYGEN__)

  /**

   * @brief Assert function to check a given condition.

   *

   * @param[in] condition   The condition to check.

   */

  void urtDebugAssert(const bool condition);

#endif /* !defined(urtDebugAssert) */

#if defined(__cplusplus)

}

#endif /* defined(__cplusplus) */

/*============================================================================*/

/* MUTEX                                                                      */

/*============================================================================*/

/*

 * The following type must be defined by the implementation:

 *

 * urt_osMutex_t

 *    Type to represent a mutex lock object.

 *    Is only used via pointers by the API.

 */

#if defined(__cplusplus)

extern "C" {

#endif /* defined(__cplusplus) */

#if !defined(urtMutexInit) || defined(__DOXYGEN__)

  /**

   * @brief   Initialize a mutex lock object.

   *

   * @param[in] mutex   Pointer to the mutex lock object to initialize.

   *                    Must not be NULL.

   */

  void urtMutexInit(urt_osMutex_t* mutex);

#endif /* !defined(urtMutexInit) */

#if !defined(urtMutexLock) || defined(__DOXYGEN__)

  /**

   * @brief   Lock a mutex lock.

   * @details The calling thread is blocked until the mutex lock could be acquired.

   *

   * @param[in] mutex   Pointer to the mutex lock to acquire.

   *                    Must not be NULL.

   */

  void urtMutexLock(urt_osMutex_t* mutex);

#endif /* !defined(urtMutexLock) */

#if !defined(urtMutexTryLock) || defined(__DOXYGEN__)

  /**

   * @brief   Try to lock a mutex lock.

   * @details This function does not block but returns immediately.

   *

   * @param[in] mutex   Pointer to the mutex lock to acquire.

   *

   * @return  Indicator whether the lock was acquired.

   * @retval true   The lock was acquired successfully.

   * @retval false  The lock could not be acquired.

   */

  bool urtMutexTryLock(urt_osMutex_t* mutex);

#endif /* !defined(urtMutexTryLock) */

#if !defined(urtMutexUnlock) || defined(__DOXYGEN__)

  /**

   * @brief   Unlock an owned mutex lock.

   *

   * @param[in] mutex   Pointer to the mutex lock to unlock.

   *                    Must not be NULL.

   */

  void urtMutexUnlock(urt_osMutex_t* mutex);

#endif /* !defined(urtMutexUnlock) */

#if defined(__cplusplus)

}

#endif /* defined(__cplusplus) */

/*============================================================================*/

/* CONDITION VARIABLE                                                         */

/*============================================================================*/

/*

 * The following type must be defined by the implementation:

 *

 * urt_osCondvar_t

 *    Type to represent a condition variable object.

 *    Is only used via pointers by the API.

 */

/**

 * @brief   Status type of condition variables.

 */

typedef enum {

  URT_CONDVAR_WAITSTATUS_SIGNAL = 1,    /**< The condition variable has been signaled individually. */

  URT_CONDVAR_WAITSTATUS_BROADCAST = 2, /**< The condition variable has been signal via broadcast. */

  URT_CONDVAR_WAITSTATUS_TIMEOUT = 0,   /**< Waiting for the condition variable timed out. */

} urt_osCondvarWaitStatus_t;

#if defined(__cplusplus)

extern "C" {

#endif /* defined(__cplusplus) */

#if !defined(urtCondvarInit) || defined(__DOXYGEN__)

  /**

   * @brief   Initialize a condition variable object.

   *

   * @param[in] condvar   Pointer to the object to initialize.

   *                      Must not be NULL.

   */

  void urtCondvarInit(urt_osCondvar_t* condvar);

#endif /* !defined(urtCondvarInit) */

#if !defined(urtCondvarSignal) || defined(__DOXYGEN__)

  /**

   * @brief   Signal a condition variable (wake one waiting thread).

   *

   * @param[in] condvar   Pointer to the condition variable to signal.

   *                      Must not be NULL.

   */

  void urtCondvarSignal(urt_osCondvar_t* condvar);

#endif /* !defined(urtCondvarSignal) */

#if !defined(urtCondvarBroadcast) || defined(__DOXYGEN__)

  /**

   * @brief   Signal a condition variable via broadcast (wake all waiting threads).

   *

   * @param[in] condvar   Pointer to the condition variable to signal via broadcast.

   *                      Must not be NULL.

   */

  void urtCondvarBroadcast(urt_osCondvar_t* condvar);

#endif /* !defined(urtCondvarBroadcast) */

#if !defined(urtCondvarWait) || defined(__DOXYGEN__)

  /**

   * @brief   Wait for a condition variable to be signaled or timeout.

   *

   * @param[in] condvar   Pointer to the condition variabel to wait for.

   *                      Must not be NULL.

   * @param[in] mutex     Pointer to the associated mutex lock.

   *                      Must not be NULL.

   *                      Mutex must be acquired when this function is called.

   * @param[in] timeout   Timeout (in microseconds) when the function will return even without the condition variable being signaled.

   *                      Use URT_DELAY_INFINITE to deactivate timeout.

   * @return

   */

  urt_osCondvarWaitStatus_t urtCondvarWait(urt_osCondvar_t* condvar, urt_osMutex_t* mutex, urt_delay_t timeout);

#endif /* !defined(urtCondvarWait) */

#if defined(__cplusplus)

}

#endif /* defined(__cplusplus) */

/*============================================================================*/

/* EVENTS                                                                     */

/*============================================================================*/

/*

 * The following types and constants must be defined by the implementation:

 *

 * urt_osEventSource_t

 *    Type to represent an event source object.

 *    Is only used via pointers by the API.

 *

 * urt_osEventListener_t

 *    Type to represent an event listener object.

 *    Is only used via pointers by the API.

 *

 * urt_osEventMask_t

 *    Integer type to represent event masks.

 *

 * urt_osEventFlags_t

 *    Integer type to represent event flags.

 *

 * URT_EVENTMASK_MAXPRIO

 *    Constant of type urt_osEventMask_t to specify the event mask that is

 *    handled with maximum priority.

 *    This constant is typically either 0x0..1 (low values have high priority)

 *    or 0x8..0 (high values have high priority).

 *    A value of 0 indicates that priorities are not supported.

 */

/**

 * @brief   Enum type to distinguish differnt variants how to wait for events.

 */

typedef enum {

  URT_EVENT_WAIT_ONE = 0,   /**< Wait for exactly one of the specified events. */

  URT_EVENT_WAIT_ANY = 1,   /**< Wait for any (one or more) of the specified events. */

  URT_EVENT_WAIT_ALL = 2,   /**< Wait for all of the specified events. */

} urt_osEventWait_t;

#if defined(__cplusplus)

extern "C" {

#endif /* defined(__cplusplus) */

#if !defined(urtEventSourceInit) || defined(__DOXYGEN__)

  /**

   * @brief   Initialize an event source object.

   *

   * @param[in] source  Pointer to the event source object to initialize.

   *                    Must not be NULL.

   */

  void urtEventSourceInit(urt_osEventSource_t* source);

#endif /* !defined(urtEventSourceInit) */

#if !defined(urtEventSourceBroadcast) || defined(__DOXYGEN__)

  /**

   * @brief   Broadcast an event with specified flags.

   *

   * @param[in] source  Pointer to the event source to broadcast the event.

   *                    Must not be NULL.

   * @param[in] flags   Flags to be set at the recieveing listeners.

   */

  void urtEventSourceBroadcast(urt_osEventSource_t* source, urt_osEventFlags_t flags);

#endif /* !defined(urtEventSourceBroadcast) */

#if !defined(urtEventListenerInit) || defined(__DOXYGEN__)

  /**

   * @brief   Initialize an event listener object.

   *          Must not be NULL.

   *

   * @param[in] listener  Pointer to the event listener object to initialize.

   */

  void urtEventListenerInit(urt_osEventListener_t* listener);

#endif /* !defined(urtEventListenerInit) */

#if !defined(urtEventListenerGetFlags) || defined(__DOXYGEN__)

  /**

   * @brief   Retrieve the currently set flags of an event listener.

   * @details Flags are not cleared in the listener.

   *

   * @param[in] listener  Pointer to the event listener to recieve the flags from.

   *                      Must not be NULL.

   *

   * @return  Currently set flags.

   */

  urt_osEventFlags_t urtEventListenerGetFlags(urt_osEventListener_t* listener);

#endif /* !defined(urtEventListenerGetFlags) */

#if !defined(urtEventListenerClearFlags) || defined(__DOXYGEN__)

  /**

   * @brief   Retrieve and clear the currently set flags from an event listener.

   *

   * @param[in] listener  Pointer to the event listener to recieve the flags from.

   *                      Must not be NULL.

   *

   * @return  The flags that had been set at the listener.

   */

  urt_osEventFlags_t urtEventListenerClearFlags(urt_osEventListener_t* listener);

#endif /* !defined(urtEventListenerClearFlags) */

#if !defined(urtEventRegister) || defined(__DOXYGEN__)

  /**

   * @brief   Register an event source to a listener.

   *

   * @param[in] source    Pointer to the event source to register.

   *                      Must not be NULL.

   * @param[in] listener  Pointer to the event listener to register.

   *                      Must not be NULL.

   * @param[in] mask      Mask to be set at the listening thread on an event.

   * @param[in] flags     Flags to be set by default at the listener on an event,

   */

  void urtEventRegister(urt_osEventSource_t* source, urt_osEventListener_t* listener, urt_osEventMask_t mask, urt_osEventFlags_t flags);

#endif /* !defined(urtEventRegister) */

#if !defined(urtEventUnregister) || defined(__DOXYGEN__)

  /**

   * @brief   Unregister an associated event source and listener.

   *

   * @param[in] source    Pointer to the event source to unregister.

   *                      Must not be NULL.

   * @param[in] listener  Pointer to the event listener to unregister.

   *                      Must not be NULL.

   */

  void urtEventUnregister(urt_osEventSource_t* source, urt_osEventListener_t* listener);

#endif /* !defined(urtEventUnregister) */

#if !defined(urtEventWait) || defined(__DOXYGEN__)

  /**

   * @brief   Wait for one/any/all event(s) to be recieved or a timeout.

   *

   * @param[in] mask      The mask of event to wait for.

   * @param[in] type      Specificator whether to wait for exactly one, any combination or all of the specified mask flags.

   * @param[in] timeout   Timeout when the function shall return even if no event was recieved.

   *

   * @return  The recieved event mask.

   */

  urt_osEventMask_t urtEventWait(urt_osEventMask_t mask, urt_osEventWait_t type, urt_delay_t timeout);

#endif /* !defined(urtEventWait) */

#if defined(__cplusplus)

}

#endif /* defined(__cplusplus) */

/*============================================================================*/

/* STREAMS                                                                    */

/*============================================================================*/

#if defined(__cplusplus)

extern "C" {

#endif /* defined(__cplusplus) */

#if !defined(urtPrintf) || defined(__DOXYGEN__)

  /**

   * @brief   Prints a formatted string to standard output.

   *

   * @param[in] fmt   The formatted string to be printed.

   *

   * @return  Number of characters printed.

   */

  int urtPrintf(char* fmt, ...);

#endif /* !defined(urtPrintf) */

#if !defined(urtErrPrintf) || defined(__DOXYGEN__)

  /**

   * @brief   Prints a formatted string to error output.

   *

   * @param[in] fmt   The formatted string to be printed.

   *

   * @return  Number of characters printed.

   */

  int urtErrPrintf(char* fmt, ...);

#endif /* !defined(urtErrPrintf) */

#if defined(__cplusplus)

}

#endif /* defined(__cplusplus) */

/*============================================================================*/

/* TIME                                                                       */

/*============================================================================*/

/*

 * The following type must be defined by the implementation:

 *

 * urt_osTime_t

 *    Type to represent a time object.

 *    This type may be of any precision.

 *    Is only used via pointers by the API.

 */

#if defined(__cplusplus)

extern "C" {

#endif /* defined(__cplusplus) */

#if !defined(urtTime2Us) || defined(__DOXYGEN__)

  /**

   * @brief   Convert an OS time to microsecond value.

   *

   * @param[in] t   The time to convert.

   *                Must not be NULL

   *

   * @return  The equivalent time in microseconds.

   */

  uint64_t urtTime2Us(urt_osTime_t* t);

#endif /* !defined(urtTime2Us) */

#if !defined(urtTimeNow) || defined(__DOXYGEN__)

  /**

   * @brief   Get the current system time.

   *

   * @return  Current system time as provide by the operating system.

   */

  urt_osTime_t urtTimeNow(void);

#endif /* !defined(urtTimeNow) */

#if !defined(urtTimeAddUs) || defined(__DOXYGEN__)

  /**

   * @brief   Add microseconds to a specified system time.

   *

   * @param[in] time    Pointer to the time value to be incremented.

   *                    Must not be NULL.

   * @param[in] offset  Amount of microseconds to add.

   */

  void urtTimeAddUs(urt_osTime_t* time, urt_delay_t offset);

#endif /* !defined(urtTimeAddUs) */

#if defined(__cplusplus)

}

#endif /* defined(__cplusplus) */

/*============================================================================*/

/* THREAD                                                                     */

/*============================================================================*/

/*

 * The following types, constants and macros must be defined by the

 * implementation:

 *

 * urt_osThread_t

 *    Type to represent an thread object.

 *    Is only used via pointers by the API.

 *

 * urt_osThreadPrio_t

 *    Integer type to represent thread priorities.

 *

 * URT_THREAD_PRIO_LOW_MIN

 *    Constant of type urt_osThreadPrio_t, specifying the minimum priority for

 *    low-priority threads.

 *    Must be greater than the idle thread priority.

 *

 * URT_THREAD_PRIO_LOW_MAX

 *    Constant of type urt_osThreadPrio_t, specifying the maximum priority for

 *    low-priority threads.

 *    Must be greater or equal URT_THREAD_PRIO_LOW_MIN.

 *

 * URT_THREAD_PRIO_NORMAL_MIN

 *    Constant of type urt_osThreadPrio_t, specifying the minimum priority for

 *    normal-priority threads.

 *    Must be greater than URT_THREAD_PRIO_LOW_MAX.

 *

 * URT_THREAD_PRIO_NORMAL_MAX

 *    Constant of type urt_osThreadPrio_t, specifying the maximum priority for

 *    normal-priority threads.

 *    Must be greater or equal URT_THREAD_PRIO_NORMAL_MIN.

 *

 * URT_THREAD_PRIO_HIGH_MIN

 *    Constant of type urt_osThreadPrio_t, specifying the minimum priority for

 *    high-priority threads.

 *    Must be greater than URT_THREAD_PRIO_NORMAL_MAX.

 *

 * URT_THREAD_PRIO_HIGH_MAX

 *    Constant of type urt_osThreadPrio_t, specifying the maximum priority for

 *    high-priority threads.

 *    Must be greater or equal URT_THREAD_PRIO_HIGH_MIN.

 *

 * URT_THREAD_PRIO_RT_MIN

 *    Constant of type urt_osThreadPrio_t, specifying the minimum priority for

 *    real-time threads.

 *    Must be greater than URT_THREAD_PRIO_HIGH_MAX.

 *

 * URT_THREAD_PRIO_RT_MAX

 *    Constant of type urt_osThreadPrio_t, specifying the maximum priority for

 *    real-time threads.

 *    Must be greater or equal URT_THREAD_PRIO_HIGH_MIN but lower than the

 *    control/root thread priority.

 *

 * URT_THREAD_SLEEP_MAX

 *    Constant of type float specifying the maximum time (in seconds) a thread

 *    may sleep via the urtThreadSleep() function.

 *

 * URT_THREAD_SSLEEP_MAX

 *    Constant of type urt_delay_t specifying the maximum number of seconds a

 *    thread may sleep via the urtThreadSSleep() function.

 *

 * URT_THREAD_MSLEEP_MAX

 *    Constant of type urt_delay_t specifying the maximum number of milliseconds

 *    a thread may sleep via the urtThreadMSleep() function.

 *

 * URT_THREAD_USLEEP_MAX

 *    Constant of type urt_delay_t specifying the maximum number of microseconds

 *    a thread may sleep via the urtThreadUSleep() function.

 *

 * URT_THREAD_MEMORY(varname, stacksize)

 *    Macro function to staically allocate a variable 'varname', which holds all

 *    memory required to hold a thread object with the specified stacksize.

 */

/**

 * @brief   Enum type for various thread states.

 */

typedef enum {

  URT_THREAD_STATE_INACTIVE = 0,    /**< The thread has not been started yet. */

  URT_THREAD_STATE_RUNNING = 1,     /**< The thread is currently being executed on a CPU. */

  URT_THREAD_STATE_READY = 2,       /**< The thread is ready to be scheduled for execution. */

  URT_THREAD_STATE_SLEEPING = 3,    /**< The thread is currently sleeping for a defined amount of time. */

  URT_THREAD_STATE_SUSPENDED = 4,   /**< Execution of the thread has been suspended. */

  URT_THREAD_STATE_WAITING = 5,     /**< The thread is currently waiting for an event. */

  URT_THREAD_STATE_TERMINATED = 6,  /**< The thread has been terminated. */

} urt_osThreadState_t;

/**

 * @brief   Enum type for various termination signals.

 */

typedef enum {

  URT_THREAD_TERMINATE_REQUEST = 15,  /**< Request a thread to terminate in a cooperative manner. */

  URT_THREAD_TERMINATE_KILL = 9,      /**< Terminate a thread in a non-cooperative manner (force). */

} urt_osThreadTerminateSignal_t;

/**

 * @brief   Thread function.

 *

 * @param[in] arg   Pointer to optional arguments.

 *                  May be NULL.

 */

typedef void (*urt_osThreadFunction_t)(void* arg);

#if defined(__cplusplus)

extern "C" {

#endif /* defined(__cplusplus) */

#if !defined(urtThreadInit) || defined(__DOXYGEN__)

  /**

   * @brief   Initialize a thread object.

   * @details The new thread becomes a child of the calling thread.

   *

   * @param[in] memory  Pointer to the memory where to create the thread object.

   *                    Must not be NULL.

   * @param[in] size    Size of the memory.

   * @param[in] prio    Initial priority of the thread.

   * @param[in] func    Pointer to the thread function the thread shall execute.

   *                    Must not be NULL.

   * @param[in] arg     Pointer to optional function arguments.

   *                    May be NULL.

   *

   * @return  Pointer to the created thread object.

   */

  urt_osThread_t* urtThreadInit(void* memory, size_t size, urt_osThreadPrio_t prio, urt_osThreadFunction_t func, void* arg);

#endif /* !defined(urtThreadInit) */

#if !defined(urtThreadStart) || defined(__DOXYGEN__)

  /**

   * @brief   Start execution of a thread.

   *

   * @param[in] thread  Pointer to the thread to start.

   *                    Must not be NULL.

   */

  void urtThreadStart(urt_osThread_t* thread);

#endif /* !defined(urtThreadStart) */

#if !defined(urtThreadYield) || defined(__DOXYGEN__)

  /**

   * @brief   Yield execution of the calling thread.

   */

  void urtThreadYield(void);

#endif /* !defined(urtThreadYield) */

#if !defined(urtThreadGetPriority) || defined(__DOXYGEN__)

  /**

   * @brief   Retrieve the current priority of the calling thread.

   *

   * @return  Current priority.

   */

  urt_osThreadPrio_t urtThreadGetPriority(void);

#endif /* !defined(urtThreadGetPriority) */

#if !defined(urtThreadSetPriority) || defined(__DOXYGEN__)

  /**

   * @brief   Set the priority of the calling thread.

   *

   * @param[in] prio  The new priority to set.

   */

  void urtThreadSetPriority(urt_osThreadPrio_t prio);

#endif /* !defined(urtThreadSetPriority) */

#if !defined(urtThreadSleep) || defined(__DOXYGEN__)

  /**

   * @brief   The calling thread sleeps for the given amount of time.

   *

   * @param[in] seconds   Time in seconds to sleep.

   *                      Must not be greater than URT_THREAD_SLEEP_MAX.

   */

  void urtThreadSleep(float seconds);

#endif /* !defined(urtThreadSleep) */

#if !defined(urtThreadSSleep) || defined(__DOXYGEN__)

  /**

   * @brief   The calling thread sleeps for the given amount of seconds.

   *

   * @param[in] seconds   Time in seconds to sleep.

   *                      Must not be greater than URT_THREAD_SSLEP_MAX.

   */

  void urtThreadSSleep(unsigned int seconds);

#endif /* !defined(urtThreadSSleep) */

#if !defined(urtThreadMSleep) || defined(__DOXYGEN__)

  /**

   * @brief   The calling thread sleeps for the given amount of milliseconds.

   *

   * @param[in] milliseconds  Time in milliseconds to sleep.

   *                          Must not be greater than URT_THREAD_MSLEP_MAX.

   */

  void urtThreadMSleep(unsigned int milliseconds);

#endif /* !defined(urtThreadMSleep) */

#if !defined(urtThreadUSleep) || defined(__DOXYGEN__)

  /**

   * @brief   The calling thread sleeps for the gven amount of microseconds.

   *

   * @param[in] microseconds  Time in microseconds to sleep.

   *                          Must not be greater than URT_THREAD_USLEP_MAX.

   */

  void urtThreadUSleep(urt_delay_t microseconds);

#endif /* !defined(urtThreadUSleep) */

#if !defined(urtThreadSleepUntil) || defined(__DOXYGEN__)

  /**

   * @brief   The calling thread sleeps until the given point in time.

   *

   * @param[in] time  Time when the thread shall wake up.

   *                  If the current is already beyond the argument, the thread will not sleep at all.

   */

  void urtThreadSleepUntil(urt_osTime_t time);

#endif /* !defined(urtThreadSleepUntil) */

#if !defined(urtThreadExit) || defined(__DOXYGEN__)

  /**

   * @brief   The calling thread stops execution and terminates.

   */

  void urtThreadExit(void);

#endif /* !defined(urtThreadExit) */

#if !defined(urtThreadTerminate) || defined(__DOXYGEN__)

  /**

   * @brief   Send a termination signal to a thread.

   *

   * @param[in] thread  Thread to be signaled.

   *                    Must not be NULL.

   * @param[in] sig     Type of termination.

   */

  void urtThreadTerminate(urt_osThread_t* thread, urt_osThreadTerminateSignal_t sig);

#endif /* !defined(urtThreadTerminate) */

#if !defined(urtThreadJoin) || defined(__DOXYGEN__)

  /**

   * @brief   Wait for a thread to terminate.

   *

   * @param[in] thread  Pointer to the thread to wait for.

   *                    Must not be NULL.

   */

  void urtThreadJoin(urt_osThread_t* thread);

#endif /* !defined(urtThreadJoin) */

#if !defined(urtThreadGetState) || defined(__DOXYGEN__)

  /**

   * @brief   Get the current execution status of a thread.

   *

   * @param[in] thread  Pointer to the thread to get the status for.

   *                    Must not be NULL.

   *

   * @return  Execution status of the secified thread.

   */

  urt_osThreadState_t urtThreadGetState(urt_osThread_t* thread);

#endif /* !defined(urtThreadGetState) */

#if !defined(urtThreadGetSelf) || defined(__DOXYGEN__)

  /**

   * @brief   Retrieve the thread object of the calling thread.

   *

   * @return  Pointer to the thread that is currrently executed.

   */

  urt_osThread_t* urtThreadGetSelf(void);

#endif /* !defined(urtThreadGetSelf) */

#if !defined(urtThreadGetChildren) || defined(__DOXYGEN__)

  /**

   * @brief   Retrieve the first child of a thread.

   *

   * @param[in] thread  Pointer to the thread to retrieve the child from.

   *                    Must not be NULL.

   *

   * @return  Pointer to the first child thread.

   *          May be NULL if the thread has no children.

   */

  urt_osThread_t* urtThreadGetChildren(urt_osThread_t* thread);

#endif /* !defined(urtThreadGetChildren) */

#if !defined(urtThreadGetSibling) || defined(__DOXYGEN__)

  /**

   * @brief   Retrieve the next sibling of a thread.

   *

   * @param[in] thread  Pointer to the thread to retrieve the sibling from.

   *

   * @return  Pointer to the next sibling of the thread.

   *          May be NULL if the thread does not have any more siblings.

   */

  urt_osThread_t* urtThreadGetSibling(urt_osThread_t* thread);

#endif /* !defined(urtThreadGetSibling) */

#if !defined(urtThreadGetParent) || defined(__DOXYGEN__)

  /**

   * @brief   Retrieve the parent of a thread.

   *

   * @param[in] thread  Pointer to the thread to retrieve the parent from.

   *

   * @return  Pointer to the parent thread.

   *          May be NULL if the specified thread is root.

   */

  urt_osThread_t* urtThreadGetParent(urt_osThread_t* thread);

#endif /* !defined(urtThreadGetParent) */

#if defined(__cplusplus)

}

#endif /* defined(__cplusplus) */

/*============================================================================*/

/* TIMER                                                                      */

/*============================================================================*/

/*

 * The following type must be defined by the implementation:

 *

 * urt_osTimer_t

 *    Type to represent a timer object.

 *    Is only used via pointers by the API.

 */

/**

 * @brief   Timer callback function type.

 * @details A timer executes a callback when its time ran out and it fires.

 *

 * @param[in] params  Pointer to optional parameters for the callback function.

 *                    May be NULL.

 */

typedef void (*urt_osTimerCallback_t)(void* parameter);

#if defined(__cplusplus)

extern "C" {

#endif /* defined(__cplusplus) */

#if !defined(urtTimerInit) || defined(__DOXYGEN__)

  /**

   * @brief   Initialize a timer object.

   *

   * @param[in] timer   Pointer to the timer object to initialize.

   *                    Must not be NULL.

   */

  void urtTimerInit(urt_osTimer_t* timer);

#endif /* !defined(urtTimerInit) */

#if !defined(urtTimerSet) || defined(__DOXYGEN__)

  /**

   * @brief   Set a timer in single-shot mode.

   *

   * @param[in] timer     Pointer to the timer to be armed.

   *                      Must not be NULL.

   * @param[in] delay     Time after which the timer shall fire.

   * @param[in] callback  Pointer to the function to be called when the timer fires.

   *                      Must not be NULL.

   * @param[in] cbparams  Optional parameters for the callback function.

   *                      May be NULL.

   */

  void urtTimerSet(urt_osTimer_t* timer, urt_delay_t delay, urt_osTimerCallback_t callback, void* cbparams);

#endif /* !defined(urtTimerSet) */

#if !defined(urtTimerSetPeriodic) || defined(__DOXYGEN__)

  /**

   * @brief   Set a timer in periodic mode.

   *

   * @param[in] timer     Pointer to the timer to be armed.

   *                      Must not be NULL.

   * @param[in] period    Time after which the timer shall fire periodically.

   * @param[in] callback  Pointer to the function to be called each time the timer fires.

   *                      Must not be NULL.

   * @param[in] cbparams  Optional parameters for the callback function.

   *                      May be NULL.

   */

  void urtTimerSetPeriodic(urt_osTimer_t* timer, urt_delay_t period, urt_osTimerCallback_t callback, void* cbparams);

#endif /* !defined(urtTimerSetPeriodic) */

#if !defined(urtTimerReset) || defined(__DOXYGEN__)

  /**

   * @brief   Reset and disarm a timer.

   *

   * @param[in] timer   Pointer to the timer to be reset.

   *                    Must not be NULL.

   */

  void urtTimerReset(urt_osTimer_t* timer);

#endif /* !defined(urtTimerReset) */

#if !defined(urtTimerIsArmed) || defined(__DOXYGEN__)

  /**

   * @brief   Retrieve the current status of a timer.

   *

   * @param[in] timer   Pointer to the timer to inspect.

   *                    Must not be NULL.

   *

   * @return  Flag, indicating whether or not the timer is currently armed.

   */

  bool urtTimerIsArmed(urt_osTimer_t* timer);

#endif /* !defined(urtTimerIsArmed) */

#if defined(__cplusplus)

}

#endif /* defined(__cplusplus) */

#endif /* URT_OSAL_H */