fg_barrier.c File Reference

Missing pthread barrier implemenation for OS X. More...

#include <config.h>
#include <pthread.h>
#include <errno.h>
#include "fg_definitions.h"
#include "fg_barrier.h"

Go to the source code of this file.

Functions
int	pthread_barrier_destroy (pthread_barrier_t *barrier)
	Destroys the barrier referenced by barrier. More...
int	pthread_barrier_init (pthread_barrier_t *barrier, const pthread_barrierattr_t *attr, unsigned count)
	Allocates resources required to use the barrier referenced by barrier. More...
int	pthread_barrier_wait (pthread_barrier_t *barrier)
	Synchronizes participating threads at the barrier referenced by barrier. More...

Detailed Description

Missing pthread barrier implemenation for OS X.

Definition in file fg_barrier.c.

Function Documentation

pthread_barrier_destroy()

int pthread_barrier_destroy

(

pthread_barrier_t *

barrier

)

Destroys the barrier referenced by barrier.

It releases any resources used by the barrier. Subsequent use of the barrier is undefined until the barrier is reinitialized by pthread_barrier_init().

Parameters

[in]

barrier

barrier that should be initialized

Returns

return 0 for success, or -1 for failure (in which case errno is set appropriately)

Definition at line 64 of file fg_barrier.c.

{
        if (unlikely(!barrier)) {
                errno = EINVAL;
                return -1;
        }
 
        if (pthread_cond_destroy(&barrier->cond) != 0)
                return -1;
 
        if (pthread_mutex_destroy(&barrier->mutex) != 0)
                return -1;
 
        return 0;
}

pthread_barrier_init()

int pthread_barrier_init	(	pthread_barrier_t *	barrier,
		const pthread_barrierattr_t *	attr,
		unsigned	count
	)

Allocates resources required to use the barrier referenced by barrier.

It initializes the barrier with attributes referenced by attr. If attr is NULL, the default barrier attributes are used.

Parameters

[in]	barrier	barrier that should be initialized
[in]	attr	NULL, or the attributes attr that barrier should use
[in]	count	number of threads that must call pthread_barrier_wait() before any of them successfully returns. Value must be greater than zero

Returns

return 0 for success, or -1 for failure (in which case errno is set appropriately)

Definition at line 37 of file fg_barrier.c.

{
        if (unlikely(!barrier) || unlikely(count == 0)) {
                errno = EINVAL;
                return -1;
        }
 
        if (attr && (*attr != PTHREAD_PROCESS_PRIVATE)) {
                errno = EINVAL;
                return -1;
        }
 
        if (pthread_mutex_init(&barrier->mutex, NULL) != 0)
                return -1;
 
        if (pthread_cond_init(&barrier->cond, NULL) != 0) {
                pthread_mutex_destroy(&barrier->mutex);
                return -1;
        }
 
        barrier->tripCount = count;
        barrier->count = 0;
 
        return 0;
}

pthread_barrier_wait()

int pthread_barrier_wait

(

pthread_barrier_t *

barrier

)

Synchronizes participating threads at the barrier referenced by barrier.

The calling thread blocks until the required number of threads have called pthread_barrier_wait(), specifying the barrier.

Parameters

[in]

barrier

barrier that should be initialized

Returns

return 0 for success, or -1 for failure (in which case errno is set appropriately)

Definition at line 80 of file fg_barrier.c.

{
        if (unlikely(!barrier)) {
                errno = EINVAL;
                return -1;
        }
 
        if (pthread_mutex_lock(&barrier->mutex) !=0)
                return -1;
        ++(barrier->count);
 
        /* No remaining pthreads, broadcast to wake all waiting threads */
        if (barrier->count >= barrier->tripCount) {
                barrier->count = 0;
                pthread_cond_broadcast(&barrier->cond);
        } else {
                pthread_cond_wait(&barrier->cond, &(barrier->mutex));
        }
 
        pthread_mutex_unlock(&barrier->mutex);
 
        return 0;
}