111 lines
3.2 KiB
C
111 lines
3.2 KiB
C
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/*
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* -------------------------------------------------------------
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*
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* Module: sem_getvalue.c
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*
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* Purpose:
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* Semaphores aren't actually part of PThreads.
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* They are defined by the POSIX Standard:
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*
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* POSIX 1003.1-2001
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*
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* -------------------------------------------------------------
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*
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* --------------------------------------------------------------------------
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*
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* Pthreads-win32 - POSIX Threads Library for Win32
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* Copyright(C) 1998 John E. Bossom
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* Copyright(C) 1999,2005 Pthreads-win32 contributors
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*
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* Contact Email: rpj@callisto.canberra.edu.au
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*
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* The current list of contributors is contained
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* in the file CONTRIBUTORS included with the source
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* code distribution. The list can also be seen at the
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* following World Wide Web location:
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* http://sources.redhat.com/pthreads-win32/contributors.html
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library in the file COPYING.LIB;
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* if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
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*/
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#include "pthread.h"
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#include "semaphore.h"
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#include "implement.h"
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int
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sem_getvalue (sem_t * sem, int *sval)
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/*
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* ------------------------------------------------------
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* DOCPUBLIC
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* This function stores the current count value of the
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* semaphore.
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* RESULTS
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*
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* Return value
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*
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* 0 sval has been set.
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* -1 failed, error in errno
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*
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* in global errno
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*
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* EINVAL 'sem' is not a valid semaphore,
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* ENOSYS this function is not supported,
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*
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*
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* PARAMETERS
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*
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* sem pointer to an instance of sem_t
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*
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* sval pointer to int.
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*
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* DESCRIPTION
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* This function stores the current count value of the semaphore
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* pointed to by sem in the int pointed to by sval.
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*/
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{
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if (sem == NULL || *sem == NULL || sval == NULL)
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{
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errno = EINVAL;
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return -1;
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}
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else
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{
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long value;
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register sem_t s = *sem;
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int result = 0;
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if ((result = pthread_mutex_lock(&s->lock)) == 0)
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{
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/* See sem_destroy.c
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*/
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if (*sem == NULL)
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{
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(void) pthread_mutex_unlock (&s->lock);
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errno = EINVAL;
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return -1;
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}
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value = s->value;
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(void) pthread_mutex_unlock(&s->lock);
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*sval = value;
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}
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return result;
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}
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} /* sem_getvalue */
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