xref: /aosp_15_r20/bionic/libc/include/threads.h (revision 8d67ca893c1523eb926b9080dbe4e2ffd2a27ba1)
1 /*
2  * Copyright (C) 2019 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 #pragma once
30 
31 /**
32  * @file threads.h
33  * @brief C11 threads.
34  */
35 
36 #include <sys/cdefs.h>
37 
38 #include <pthread.h>
39 #include <time.h>
40 
41 #define ONCE_FLAG_INIT PTHREAD_ONCE_INIT
42 #define TSS_DTOR_ITERATIONS PTHREAD_DESTRUCTOR_ITERATIONS
43 
44 /** The type for a condition variable. */
45 typedef pthread_cond_t cnd_t;
46 /** The type for a thread. */
47 typedef pthread_t thrd_t;
48 /** The type for a thread-specific storage key. */
49 typedef pthread_key_t tss_t;
50 /** The type for a mutex. */
51 typedef pthread_mutex_t mtx_t;
52 
53 /** The type for a thread-specific storage destructor. */
54 typedef void (*tss_dtor_t)(void* _Nullable);
55 /** The type of the function passed to thrd_create() to create a new thread. */
56 typedef int (*thrd_start_t)(void* _Nullable);
57 
58 /** The type used by call_once(). */
59 typedef pthread_once_t once_flag;
60 
61 enum {
62   mtx_plain = 0x1,
63   mtx_recursive = 0x2,
64   mtx_timed = 0x4,
65 };
66 
67 enum {
68   thrd_success = 0,
69   thrd_busy = 1,
70   thrd_error = 2,
71   thrd_nomem = 3,
72   thrd_timedout = 4,
73 };
74 
75 /* `thread_local` is a keyword in C++11 and C23; C11 had `_Thread_local` instead. */
76 #if !defined(__cplusplus) && (__STDC_VERSION__ >= 201112L && __STDC_VERSION__ < 202311L)
77 # undef thread_local
78 # define thread_local _Thread_local
79 #endif
80 
81 __BEGIN_DECLS
82 
83 #if __ANDROID_API__ >= 30
84 // This file is implemented as static inlines before API level 30.
85 
86 /** Uses `__flag` to ensure that `__function` is called exactly once. */
87 void call_once(once_flag* _Nonnull __flag, void (* _Nonnull __function)(void)) __INTRODUCED_IN(30);
88 
89 
90 
91 /**
92  * Unblocks all threads blocked on `__cond`.
93  */
94 int cnd_broadcast(cnd_t* _Nonnull __cond) __INTRODUCED_IN(30);
95 
96 /**
97  * Destroys a condition variable.
98  */
99 void cnd_destroy(cnd_t* _Nonnull __cond) __INTRODUCED_IN(30);
100 
101 /**
102  * Creates a condition variable.
103  */
104 int cnd_init(cnd_t* _Nonnull __cond) __INTRODUCED_IN(30);
105 
106 /**
107  * Unblocks one thread blocked on `__cond`.
108  */
109 int cnd_signal(cnd_t* _Nonnull __cond) __INTRODUCED_IN(30);
110 
111 /**
112  * Unlocks `__mutex` and blocks until `__cond` is signaled or `__timeout` occurs.
113  */
114 int cnd_timedwait(cnd_t* _Nonnull __cond, mtx_t* _Nonnull __mutex, const struct timespec* _Nonnull __timeout)
115     __INTRODUCED_IN(30);
116 
117 /**
118  * Unlocks `__mutex` and blocks until `__cond` is signaled.
119  */
120 int cnd_wait(cnd_t* _Nonnull __cond, mtx_t* _Nonnull __mutex) __INTRODUCED_IN(30);
121 
122 
123 
124 /**
125  * Destroys a mutex.
126  */
127 void mtx_destroy(mtx_t* _Nonnull __mutex) __INTRODUCED_IN(30);
128 
129 /**
130  * Creates a mutex.
131  */
132 int mtx_init(mtx_t* _Nonnull __mutex, int __type) __INTRODUCED_IN(30);
133 
134 /**
135  * Blocks until `__mutex` is acquired.
136  */
137 int mtx_lock(mtx_t* _Nonnull __mutex) __INTRODUCED_IN(30);
138 
139 /**
140  * Blocks until `__mutex` is acquired or `__timeout` expires.
141  */
142 int mtx_timedlock(mtx_t* _Nonnull __mutex, const struct timespec* _Nonnull __timeout) __INTRODUCED_IN(30);
143 
144 /**
145  * Acquires `__mutex` or returns `thrd_busy`.
146  */
147 int mtx_trylock(mtx_t* _Nonnull __mutex) __INTRODUCED_IN(30);
148 
149 /**
150  * Unlocks `__mutex`.
151  */
152 int mtx_unlock(mtx_t* _Nonnull __mutex) __INTRODUCED_IN(30);
153 
154 
155 
156 /**
157  * Creates a new thread running `__function(__arg)`, and sets `*__thrd` to
158  * the new thread.
159  */
160 int thrd_create(thrd_t* _Nonnull __thrd, thrd_start_t _Nonnull __function, void* _Nullable __arg) __INTRODUCED_IN(30);
161 
162 /**
163  * Returns the `thrd_t` corresponding to the caller.
164  */
165 thrd_t thrd_current(void) __INTRODUCED_IN(30);
166 
167 /**
168  * Tells the OS to automatically dispose of `__thrd` when it exits.
169  */
170 int thrd_detach(thrd_t __thrd) __INTRODUCED_IN(30);
171 
172 /**
173  * Tests whether two threads are the same thread.
174  */
175 int thrd_equal(thrd_t __lhs, thrd_t __rhs) __INTRODUCED_IN(30);
176 
177 /**
178  * Terminates the calling thread, setting its result to `__result`.
179  */
180 void thrd_exit(int __result) __noreturn __INTRODUCED_IN(30);
181 
182 /**
183  * Blocks until `__thrd` terminates. If `__result` is not null, `*__result`
184  * is set to the exiting thread's result.
185  */
186 int thrd_join(thrd_t __thrd, int* _Nullable __result) __INTRODUCED_IN(30);
187 
188 /**
189  * Blocks the caller for at least `__duration` unless a signal is delivered.
190  * If a signal causes the sleep to end early and `__remaining` is not null,
191  * `*__remaining` is set to the time remaining.
192  *
193  * Returns 0 on success, or -1 if a signal was delivered.
194  */
195 int thrd_sleep(const struct timespec* _Nonnull __duration, struct timespec* _Nullable __remaining) __INTRODUCED_IN(30);
196 
197 /**
198  * Request that other threads should be scheduled.
199  */
200 void thrd_yield(void) __INTRODUCED_IN(30);
201 
202 
203 
204 /**
205  * Creates a thread-specific storage key with the associated destructor (which
206  * may be null).
207  */
208 int tss_create(tss_t* _Nonnull __key, tss_dtor_t _Nullable __dtor) __INTRODUCED_IN(30);
209 
210 /**
211  * Destroys a thread-specific storage key.
212  */
213 void tss_delete(tss_t __key) __INTRODUCED_IN(30);
214 
215 /**
216  * Returns the value for the current thread held in the thread-specific storage
217  * identified by `__key`.
218  */
219 void* _Nullable tss_get(tss_t __key) __INTRODUCED_IN(30);
220 
221 /**
222  * Sets the current thread's value for the thread-specific storage identified
223  * by `__key` to `__value`.
224  */
225 int tss_set(tss_t __key, void* _Nonnull __value) __INTRODUCED_IN(30);
226 
227 #endif
228 
229 __END_DECLS
230 
231 #include <android/legacy_threads_inlines.h>
232