| /* |
| * ------------------------------------------------------------- |
| * |
| * Module: sem_init.c |
| * |
| * Purpose: |
| * Semaphores aren't actually part of PThreads. |
| * They are defined by the POSIX Standard: |
| * |
| * POSIX 1003.1-2001 |
| * |
| * ------------------------------------------------------------- |
| * |
| * Pthreads-win32 - POSIX Threads Library for Win32 |
| * Copyright(C) 1998 John E. Bossom |
| * Copyright(C) 1999,2005 Pthreads-win32 contributors |
| * |
| * Contact Email: rpj@callisto.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 "semaphore.h" |
| #include "implement.h" |
| |
| int |
| sem_init (sem_t * sem, int pshared, unsigned int value) |
| /* |
| * ------------------------------------------------------ |
| * DOCPUBLIC |
| * This function initializes a semaphore. The |
| * initial value of the semaphore is 'value' |
| * |
| * PARAMETERS |
| * sem |
| * pointer to an instance of sem_t |
| * |
| * pshared |
| * if zero, this semaphore may only be shared between |
| * threads in the same process. |
| * if nonzero, the semaphore can be shared between |
| * processes |
| * |
| * value |
| * initial value of the semaphore counter |
| * |
| * DESCRIPTION |
| * This function initializes a semaphore. The |
| * initial value of the semaphore is set to 'value'. |
| * |
| * RESULTS |
| * 0 successfully created semaphore, |
| * -1 failed, error in errno |
| * ERRNO |
| * EINVAL 'sem' is not a valid semaphore, or |
| * 'value' >= SEM_VALUE_MAX |
| * ENOMEM out of memory, |
| * ENOSPC a required resource has been exhausted, |
| * ENOSYS semaphores are not supported, |
| * EPERM the process lacks appropriate privilege |
| * |
| * ------------------------------------------------------ |
| */ |
| { |
| int result = 0; |
| sem_t s = NULL; |
| |
| if (pshared != 0) |
| { |
| /* |
| * Creating a semaphore that can be shared between |
| * processes |
| */ |
| result = EPERM; |
| } |
| else if (value > (unsigned int)SEM_VALUE_MAX) |
| { |
| result = EINVAL; |
| } |
| else |
| { |
| s = (sem_t) calloc (1, sizeof (*s)); |
| |
| if (NULL == s) |
| { |
| result = ENOMEM; |
| } |
| else |
| { |
| |
| s->value = value; |
| if (pthread_mutex_init(&s->lock, NULL) == 0) |
| { |
| |
| #ifdef NEED_SEM |
| |
| s->sem = CreateEvent (NULL, |
| PTW32_FALSE, /* auto (not manual) reset */ |
| PTW32_FALSE, /* initial state is unset */ |
| NULL); |
| |
| if (0 == s->sem) |
| { |
| free (s); |
| (void) pthread_mutex_destroy(&s->lock); |
| result = ENOSPC; |
| } |
| else |
| { |
| s->leftToUnblock = 0; |
| } |
| |
| #else /* NEED_SEM */ |
| |
| if ((s->sem = CreateSemaphore (NULL, /* Always NULL */ |
| (long) 0, /* Force threads to wait */ |
| (long) SEM_VALUE_MAX, /* Maximum value */ |
| NULL)) == 0) /* Name */ |
| { |
| (void) pthread_mutex_destroy(&s->lock); |
| result = ENOSPC; |
| } |
| |
| #endif /* NEED_SEM */ |
| |
| } |
| else |
| { |
| result = ENOSPC; |
| } |
| |
| if (result != 0) |
| { |
| free(s); |
| } |
| } |
| } |
| |
| if (result != 0) |
| { |
| errno = result; |
| return -1; |
| } |
| |
| *sem = s; |
| |
| return 0; |
| |
| } /* sem_init */ |