rmutex.h

Recursive Mutex for thread synchronization.

RIOT synchronization API

RMUTEX_INIT

Static initializer for rmutex_t.

{ MUTEX_INIT, 0, ATOMIC_VAR_INIT(KERNEL_PID_UNDEF) }

This initializer is preferable to rmutex.h::rmutex_init().

struct rmutex_t rmutex_t

Mutex structure.

Must never be modified by the user.

void rmutex_init(rmutex_t * rmutex)

Initializes a recursive mutex object.

For initialization of variables use RMUTEX_INIT instead. Only use the function call for dynamically allocated mutexes.

Parameters

rmutex:pre-allocated mutex structure, must not be NULL.

int rmutex_trylock(rmutex_t * rmutex)

Tries to get a recursive mutex, non-blocking.

Parameters

rmutex:Recursive mutex object to lock. Has to be initialized first. Must not be NULL.

Return values

• 1 if mutex was unlocked, now it is locked.
• 0 if the mutex was locked.

void rmutex_lock(rmutex_t * rmutex)

Locks a recursive mutex, blocking.

Parameters

rmutex:Recursive mutex object to lock. Has to be initialized first. Must not be NULL.

void rmutex_unlock(rmutex_t * rmutex)

Unlocks the recursive mutex.

Parameters

rmutex:Recursive mutex object to unlock, must not be NULL.

struct rmutex_t

Mutex structure.

Must never be modified by the user.

mutex_t mutex

The mutex used for locking.

Must never be changed by the user.

uint16_t refcount

Number of locks owned by the thread owner.

atomic_int_least16_t owner

Owner thread of the mutex.

Owner is written by the mutex holder, and read concurrently to ensure consistency, atomic_int_least16_t is used. Note kernel_types.h::kernel_pid_t is an int16