28 lines
1.0 KiB
C
28 lines
1.0 KiB
C
/*
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* Copyright (c) 2014, 2021 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* semaphore/sem_getvalue.c
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* Get the value of a semaphore.
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*/
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#include <semaphore.h>
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int sem_getvalue(sem_t* restrict sem, int* restrict value_ptr)
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{
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int value = __atomic_load_n(&sem->value, __ATOMIC_SEQ_CST);
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*value_ptr = value == -1 ? 0 : value;
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return 0;
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}
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