Counting semaphores

Detailed Description

Provides counting semaphore support for task synchronization.

Functions
struct mmosal_sem *	mmosal_sem_create (unsigned max_count, unsigned initial_count, const char *name)
	Create a new counting semaphore. More...
void	mmosal_sem_delete (struct mmosal_sem *sem)
	Delete the given counting semaphore. More...
bool	mmosal_sem_give (struct mmosal_sem *sem)
	Give a counting semaphore. More...
bool	mmosal_sem_give_from_isr (struct mmosal_sem *sem)
	Give a counting semaphore (from ISR context). More...
bool	mmosal_sem_wait (struct mmosal_sem *sem, uint32_t timeout_ms)
	Wait for a counting semaphore. More...
uint32_t	mmosal_sem_get_count (struct mmosal_sem *sem)
	Returns the current count of the semaphore. More...

Function Documentation

mmosal_sem_create()

struct mmosal_sem * mmosal_sem_create	(	unsigned	max_count,
		unsigned	initial_count,
		const char *	name
	)

Create a new counting semaphore.

Parameters

max_count	The maximum count (i.e., number of times the semaphore can be given).
initial_count	The initial count (i.e., number of times the semaphore is implicitly given when it is created).
name	The name of the semaphore.

Returns

an opaque handle to the semaphore, or NULL on failure.

mmosal_sem_delete()

void mmosal_sem_delete

(

struct mmosal_sem *

sem

)

Delete the given counting semaphore.

Parameters

sem	Semaphore to delete.

mmosal_sem_get_count()

uint32_t mmosal_sem_get_count

(

struct mmosal_sem *

sem

)

Returns the current count of the semaphore.

Parameters

sem	The semaphore being queried.

Returns

The count of the semaphore being queried.

mmosal_sem_give()

bool mmosal_sem_give

(

struct mmosal_sem *

sem

)

Give a counting semaphore.

Warning

May not be invoked from an ISR.

Parameters

sem	The semaphore to give.

Returns

true on success, else false.

mmosal_sem_give_from_isr()

bool mmosal_sem_give_from_isr

(

struct mmosal_sem *

sem

)

Give a counting semaphore (from ISR context).

Warning

May only be invoked from an ISR.

Parameters

sem	The semaphore to give.

Returns

true on success, else false.

mmosal_sem_wait()

bool mmosal_sem_wait	(	struct mmosal_sem *	sem,
		uint32_t	timeout_ms
	)

Wait for a counting semaphore.

Parameters

sem	The semaphore to wait for.
timeout_ms	Timeout after which to give up waiting (in milliseconds).

Returns

true if the the semaphore was taken successfully, else false.