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Diffstat (limited to 'pthreads/src/sem_init.c')
| -rw-r--r-- | pthreads/src/sem_init.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/pthreads/src/sem_init.c b/pthreads/src/sem_init.c new file mode 100644 index 0000000..f682f4b --- /dev/null +++ b/pthreads/src/sem_init.c @@ -0,0 +1,169 @@ +/* + * ------------------------------------------------------------- + * + * 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) + { + +#if defined(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 */ |