Nils O. Selåsdal
44 lines
1.2 KiB
C
44 lines
1.2 KiB
C
#ifndef UC_TICKET_LOCK_H_
|
|
#define UC_TICKET_LOCK_H_
|
|
|
|
#include <pthread.h>
|
|
|
|
/** An fair alternative to a bare pthread_mutex_t to prevent starvation*/
|
|
struct UCTicketLock {
|
|
pthread_cond_t cond;
|
|
pthread_mutex_t mutex;
|
|
unsigned long queue_head, queue_tail;
|
|
};
|
|
|
|
/** Static initializer for an UCTicketLock. Use as e.g
|
|
*
|
|
* struct UCTicketLock my_lock = UC_TICKET_LOCK_INITIALIZER;
|
|
*/
|
|
#define UC_TICKET_LOCK_INITIALIZER { PTHREAD_COND_INITIALIZER, PTHREAD_MUTEX_INITIALIZER,0, 0}
|
|
|
|
/** Initialize a UCTicketLock.
|
|
* The default attributes for the pthread mutex and condition variable is used.
|
|
*
|
|
* @return 0 on success, errno value on failure
|
|
*/
|
|
int uc_ticket_lock_init(struct UCTicketLock *lock);
|
|
|
|
/** Initialize a UCTicketLock with attributes
|
|
*
|
|
* @param mattr attribute used for the mutex, or NULL
|
|
* @param cattr attribute used for the condition variable, or NULL
|
|
*
|
|
* @return 0 on success, errno value on failure
|
|
*/
|
|
int uc_ticket_lock_init_ex(struct UCTicketLock *lock, pthread_mutexattr_t *mattr, pthread_condattr_t *cattr);
|
|
|
|
/** Acquire the lock
|
|
*/
|
|
void uc_ticket_lock(struct UCTicketLock *lock);
|
|
|
|
/** Release the lock
|
|
*/
|
|
void uc_ticket_unlock(struct UCTicketLock *lock);
|
|
|
|
#endif
|