1 /* 2 * Copyright (C) 2008 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #ifndef _SEMAPHORE_H 30 #define _SEMAPHORE_H 31 32 #include <sys/cdefs.h> 33 #include <sys/types.h> 34 35 __BEGIN_DECLS 36 37 struct timespec; 38 39 typedef struct { 40 unsigned int count; 41 #ifdef __LP64__ 42 int __reserved[3]; 43 #endif 44 } sem_t; 45 46 #define SEM_FAILED __BIONIC_CAST(reinterpret_cast, sem_t*, 0) 47 48 49 #if __BIONIC_AVAILABILITY_GUARD(30) 50 int sem_clockwait(sem_t* _Nonnull __sem, clockid_t __clock, const struct timespec* _Nonnull __ts) __INTRODUCED_IN(30); 51 #endif /* __BIONIC_AVAILABILITY_GUARD(30) */ 52 53 int sem_destroy(sem_t* _Nonnull __sem); 54 int sem_getvalue(sem_t* _Nonnull __sem, int* _Nonnull __value); 55 int sem_init(sem_t* _Nonnull __sem, int __shared, unsigned int __value); 56 int sem_post(sem_t* _Nonnull __sem); 57 int sem_timedwait(sem_t* _Nonnull __sem, const struct timespec* _Nonnull __ts); 58 /* 59 * POSIX historically only supported using sem_timedwait() with CLOCK_REALTIME, however that is 60 * typically inappropriate, since that clock can change dramatically, causing the timeout to either 61 * expire earlier or much later than intended. This function is added to use a timespec based 62 * on CLOCK_MONOTONIC that does not suffer from this issue. 63 * Note that sem_clockwait() allows specifying an arbitrary clock and has superseded this 64 * function. 65 */ 66 67 #if __BIONIC_AVAILABILITY_GUARD(28) 68 int sem_timedwait_monotonic_np(sem_t* _Nonnull __sem, const struct timespec* _Nonnull __ts) __INTRODUCED_IN(28); 69 #endif /* __BIONIC_AVAILABILITY_GUARD(28) */ 70 71 int sem_trywait(sem_t* _Nonnull __sem); 72 int sem_wait(sem_t* _Nonnull __sem); 73 74 /* These aren't actually implemented. */ 75 sem_t* _Nullable sem_open(const char* _Nonnull __name, int _flags, ...); 76 int sem_close(sem_t* _Nonnull __sem); 77 int sem_unlink(const char* _Nonnull __name); 78 79 __END_DECLS 80 81 #endif 82