Components/Libraries/XF/FreeRTOS/Mutex

Mutex

Mutexes are like BinarySemaphores but they include an inheritance mechanism. This means that if a high priority task blocks while attempting to obtain a mutex (entered) that is currently held by a lower priority task, then the priority of the task holding the token is temporarily raised to that of the blocking task.This mechanism is designed to ensure the higher priority task is kept in the blocked state for the shortest time possible, and in so doing minimize the 'priority inversion' that has already occurred.

This mechanism make that Mutexes are the best choice for implement mutual exclusion and protect critical sections.

Member Attributes

emaphoreHandle_t _mutexHandler : the FreeRTOS mutex

Member Function Descrition

Mutex()

Description

The constructor of the Mutex. It will create a free RTOS Mutex and initialize it

~Mutex()

Description

The destructor of the Mutex. It will delete the free RTOS Mutex

bool enter(timeSize oTimeToWait)

Description

Obtain the mutex (decrement count value)

Parameters

TimeToWait : maximal amount of time (in ticks) that thread should wait if mutex is not available

bool enterFromISR()

Description

Obtain the semaphore (decrement count value) from an ISR

bool exit()

Description

Release the semaphore (increment count value)

bool exitFromISR()

Description

Release the semaphore (increment count value) from an ISR

bool isCreated()

Description

This function just return true if the mutex has been created successfully, else false.