diff options
Diffstat (limited to 'barrier.c')
| -rw-r--r-- | barrier.c | 432 |
1 files changed, 34 insertions, 398 deletions
@@ -4,409 +4,45 @@ * Description: * This translation unit implements barrier primitives. * - * Pthreads-win32 - POSIX Threads Library for Win32 - * Copyright (C) 1998 Ben Elliston and Ross Johnson - * Copyright (C) 1999,2000,2001 Ross Johnson + * -------------------------------------------------------------------------- * - * Contact Email: rpj@ise.canberra.edu.au - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Library General Public - * License as published by the Free Software Foundation; either - * version 2 of the License, or (at your option) any later version. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Library General Public License for more details. - * - * You should have received a copy of the GNU Library General Public - * License along with this library; if not, write to the Free - * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, - * MA 02111-1307, USA + * Pthreads-win32 - POSIX Threads Library for Win32 + * Copyright(C) 1998 John E. Bossom + * Copyright(C) 1999,2002 Pthreads-win32 contributors + * + * Contact Email: rpj@ise.canberra.edu.au + * + * The current list of contributors is contained + * in the file CONTRIBUTORS included with the source + * code distribution. The list can also be seen at the + * following World Wide Web location: + * http://sources.redhat.com/pthreads-win32/contributors.html + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library in the file COPYING.LIB; + * if not, write to the Free Software Foundation, Inc., + * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA */ #include "pthread.h" #include "implement.h" -int -pthread_barrier_init(pthread_barrier_t * barrier, - const pthread_barrierattr_t * attr, - unsigned int count) -{ - pthread_barrier_t b; - - if (barrier == NULL || count == 0) - { - return EINVAL; - } - - if (NULL != (b = (pthread_barrier_t) calloc(1, sizeof(*b)))) - { - b->pshared = (attr != NULL && *attr != NULL - ? (*attr)->pshared - : PTHREAD_PROCESS_PRIVATE); - - b->nCurrentBarrierHeight = b->nInitialBarrierHeight = count; - b->iStep = 0; - - /* - * Two semaphores are used in the same way as two stepping - * stones might be used in crossing a stream. Once all - * threads are safely on one stone, the other stone can - * be moved ahead, and the threads can start moving to it. - * If some threads decide to eat their lunch before moving - * then the other threads have to wait. - */ - if (0 == sem_init(&(b->semBarrierBreeched[0]), b->pshared, 0)) - { - if (0 == sem_init(&(b->semBarrierBreeched[1]), b->pshared, 0)) - { - *barrier = b; - return 0; - } - (void) sem_destroy(&(b->semBarrierBreeched[0])); - } - (void) free(b); - } - - return ENOMEM; -} - -int -pthread_barrier_destroy(pthread_barrier_t *barrier) -{ - int result = 0; - pthread_barrier_t b; - - if (barrier == NULL || *barrier == (pthread_barrier_t) PTW32_OBJECT_INVALID) - { - return EINVAL; - } - - b = *barrier; - *barrier = NULL; - - if (0 == (result = sem_destroy(&(b->semBarrierBreeched[0])))) - { - if (0 == (result = sem_destroy(&(b->semBarrierBreeched[1])))) - { - (void) free(b); - return 0; - } - (void) sem_init(&(b->semBarrierBreeched[0]), - b->pshared, - 0); - } - - *barrier = b; - return(result); -} - - -int -pthread_barrier_wait(pthread_barrier_t *barrier) -{ - int result; - int step; - pthread_barrier_t b; - - if (barrier == NULL || *barrier == (pthread_barrier_t) PTW32_OBJECT_INVALID) - { - return EINVAL; - } - - b = *barrier; - step = b->iStep; - - if (0 == InterlockedDecrement((long *) &(b->nCurrentBarrierHeight))) - { - /* Must be done before posting the semaphore. */ - b->nCurrentBarrierHeight = b->nInitialBarrierHeight; - - /* - * There is no race condition between the semaphore wait and post - * because we are using two alternating semas and all threads have - * entered barrier_wait and checked nCurrentBarrierHeight before this - * barrier's sema can be posted. Any threads that have not quite - * entered sem_wait below when the multiple_post has completed - * will nevertheless continue through the semaphore (barrier) - * and will not be left stranded. - */ - result = (b->nInitialBarrierHeight > 1 - ? sem_post_multiple(&(b->semBarrierBreeched[step]), - b->nInitialBarrierHeight - 1) - : 0); - } - else - { - BOOL switchCancelState; - int oldCancelState; - pthread_t self = pthread_self(); - - /* - * This routine is not a cancelation point, so temporarily - * prevent sem_wait() from being one. - * PTHREAD_CANCEL_ASYNCHRONOUS threads can still be canceled. - */ - switchCancelState = (self->cancelType == PTHREAD_CANCEL_DEFERRED && - 0 == pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, - &oldCancelState)); - - result = sem_wait(&(b->semBarrierBreeched[step])); - - if (switchCancelState) - { - (void) pthread_setcancelstate(oldCancelState, NULL); - } - } - - /* - * The first thread across will be the PTHREAD_BARRIER_SERIAL_THREAD. - * This also sets up the alternate semaphore as the next barrier. - */ - if (0 == result) - { - result = ((PTW32_INTERLOCKED_LONG) step == - ptw32_interlocked_compare_exchange((PTW32_INTERLOCKED_LPLONG) &(b->iStep), - (PTW32_INTERLOCKED_LONG) (1L - step), - (PTW32_INTERLOCKED_LONG) step) - ? PTHREAD_BARRIER_SERIAL_THREAD - : 0); - } - - return(result); -} - - -int -pthread_barrierattr_init (pthread_barrierattr_t * attr) - /* - * ------------------------------------------------------ - * DOCPUBLIC - * Initializes a barrier attributes object with default - * attributes. - * - * PARAMETERS - * attr - * pointer to an instance of pthread_barrierattr_t - * - * - * DESCRIPTION - * Initializes a barrier attributes object with default - * attributes. - * - * NOTES: - * 1) Used to define barrier types - * - * RESULTS - * 0 successfully initialized attr, - * ENOMEM insufficient memory for attr. - * - * ------------------------------------------------------ - */ -{ - pthread_barrierattr_t ba; - int result = 0; - - ba = (pthread_barrierattr_t) calloc (1, sizeof (*ba)); - - if (ba == NULL) - { - result = ENOMEM; - } - else - { - ba->pshared = PTHREAD_PROCESS_PRIVATE; - } - - *attr = ba; - - return (result); -} /* pthread_barrierattr_init */ - - -int -pthread_barrierattr_destroy (pthread_barrierattr_t * attr) - /* - * ------------------------------------------------------ - * DOCPUBLIC - * Destroys a barrier attributes object. The object can - * no longer be used. - * - * PARAMETERS - * attr - * pointer to an instance of pthread_barrierattr_t - * - * - * DESCRIPTION - * Destroys a barrier attributes object. The object can - * no longer be used. - * - * NOTES: - * 1) Does not affect barrieres created using 'attr' - * - * RESULTS - * 0 successfully released attr, - * EINVAL 'attr' is invalid. - * - * ------------------------------------------------------ - */ -{ - int result = 0; - - if (attr == NULL || *attr == NULL) - { - result = EINVAL; - } - else - { - pthread_barrierattr_t ba = *attr; - - *attr = NULL; - free (ba); - } - - return (result); -} /* pthread_barrierattr_destroy */ - - -int -pthread_barrierattr_getpshared (const pthread_barrierattr_t * attr, - int *pshared) - /* - * ------------------------------------------------------ - * DOCPUBLIC - * Determine whether barriers created with 'attr' can be - * shared between processes. - * - * PARAMETERS - * attr - * pointer to an instance of pthread_barrierattr_t - * - * pshared - * will be set to one of: - * - * PTHREAD_PROCESS_SHARED - * May be shared if in shared memory - * - * PTHREAD_PROCESS_PRIVATE - * Cannot be shared. - * - * - * DESCRIPTION - * Mutexes creatd with 'attr' can be shared between - * processes if pthread_barrier_t variable is allocated - * in memory shared by these processes. - * NOTES: - * 1) pshared barriers MUST be allocated in shared - * memory. - * 2) The following macro is defined if shared barriers - * are supported: - * _POSIX_THREAD_PROCESS_SHARED - * - * RESULTS - * 0 successfully retrieved attribute, - * EINVAL 'attr' is invalid, - * - * ------------------------------------------------------ - */ -{ - int result; - - if ((attr != NULL && *attr != NULL) && - (pshared != NULL)) - { - *pshared = (*attr)->pshared; - result = 0; - } - else - { - result = EINVAL; - } - - return (result); -} /* pthread_barrierattr_getpshared */ - +#include "barrier_init.c" +#include "barrier_destroy.c" +#include "barrier_wait.c" +#include "barrier_attr_init.c" +#include "barrier_attr_destroy.c" +#include "barrier_attr_getpshared.c" +#include "barrier_attr_setpshared.c" -int -pthread_barrierattr_setpshared (pthread_barrierattr_t * attr, - int pshared) - /* - * ------------------------------------------------------ - * DOCPUBLIC - * Barriers created with 'attr' can be shared between - * processes if pthread_barrier_t variable is allocated - * in memory shared by these processes. - * - * PARAMETERS - * attr - * pointer to an instance of pthread_barrierattr_t - * - * pshared - * must be one of: - * - * PTHREAD_PROCESS_SHARED - * May be shared if in shared memory - * - * PTHREAD_PROCESS_PRIVATE - * Cannot be shared. - * - * DESCRIPTION - * Mutexes creatd with 'attr' can be shared between - * processes if pthread_barrier_t variable is allocated - * in memory shared by these processes. - * - * NOTES: - * 1) pshared barriers MUST be allocated in shared - * memory. - * - * 2) The following macro is defined if shared barriers - * are supported: - * _POSIX_THREAD_PROCESS_SHARED - * - * RESULTS - * 0 successfully set attribute, - * EINVAL 'attr' or pshared is invalid, - * ENOSYS PTHREAD_PROCESS_SHARED not supported, - * - * ------------------------------------------------------ - */ -{ - int result; - - if ((attr != NULL && *attr != NULL) && - ((pshared == PTHREAD_PROCESS_SHARED) || - (pshared == PTHREAD_PROCESS_PRIVATE))) - { - if (pshared == PTHREAD_PROCESS_SHARED) - { - -#if !defined( _POSIX_THREAD_PROCESS_SHARED ) - - result = ENOSYS; - pshared = PTHREAD_PROCESS_PRIVATE; - -#else - - result = 0; - -#endif /* _POSIX_THREAD_PROCESS_SHARED */ - - } - else - { - result = 0; - } - - (*attr)->pshared = pshared; - } - else - { - result = EINVAL; - } - - return (result); - -} /* pthread_barrierattr_setpshared */ |