locks.h File Reference

Go to the source code of this file.

Data Structures
struct	semaphore_t
struct	mutex_t
Functions
semaphore_t	semaphores_create (int count)
	Creates a semaphore.
void	semaphores_lock (semaphore_t *s)
	Locks a semaphore.
int	semaphores_lock_noblock (semaphore_t *s)
	Locks a semaphore.
void	semaphores_unlock (semaphore_t *s)
	Unlocks a semaphore.
mutex_t	mutexes_create (void)
	Creates a mutex.
void	mutexes_lock (mutex_t *m)
	Locks a mutex.
int	mutexes_lock_noblock (mutex_t *m)
	Locks a mutex.
void	mutexes_unlock (mutex_t *m)
	Unlocks a mutex.

---

Detailed Description

Locking API for libthreads.

Todo:

Semaphores and mutexes should have a queue of threads that are waiting for a lock, then wake one whenever the lock is unlocked. (thanks tueidj)

---

Function Documentation

mutex_t mutexes_create

(

void

)

Creates a mutex.

Returns:

A mutex object.

void mutexes_lock

(

mutex_t *

m

)

Locks a mutex.

This call is BLOCKING, using sleep mode. Do not use this function inside of an interrupt handler, nor within a threads_freeze() block.

Parameters:

m

a pointer to the mutex to lock.

See also:

mutexes_lock_noblock(), mutexes_unlock()

int mutexes_lock_noblock

(

mutex_t *

m

)

Locks a mutex.

This call is nonblocking, thus it is safe to use within an interrupt handler or a threads_freeze() block. It will return no matter whether it succeeded or failed.

Parameters:

m

a pointer to the mutex to lock.

Returns:

1 if the mutex was able to be locked, 0 if it was not.

See also:

mutexes_lock(), mutexes_unlock()

void mutexes_unlock

(

mutex_t *

m

)

Unlocks a mutex.

Parameters:

m

a pointer to the mutex to unlock.

See also:

mutexes_lock_noblock(), mutexes_lock()

semaphore_t semaphores_create

(

int

count

)

Creates a semaphore.

Parameters:

count

how many locks the semaphore may take before waiting.

Returns:

A semaphore object with the requested specification.

void semaphores_lock

(

semaphore_t *

s

)

Locks a semaphore.

This call is BLOCKING, using sleep mode. Do not use this function inside of an interrupt handler, nor within a threads_freeze() block.

Parameters:

s

a pointer to the semaphore to lock.

See also:

semaphores_lock_noblock(), semaphores_unlock()

int semaphores_lock_noblock

(

semaphore_t *

s

)

Locks a semaphore.

This call is nonblocking, thus it is safe to use within an interrupt handler or a threads_freeze() block. It will return no matter whether it succeeded or failed.

Parameters:

s

a pointer to the semaphore to lock.

Returns:

1 if the semaphore was able to be locked, 0 if it was not.

See also:

semaphores_lock(), semaphores_unlock()

void semaphores_unlock

(

semaphore_t *

s

)

Unlocks a semaphore.

Unlocks a semaphore by a single level.

Parameters:

s

a pointer to the semaphore to unlock.

See also:

semaphores_lock_noblock(), semaphores_lock()