1 /* 2 * Copyright (c) 2023 Huawei Device Co., Ltd. 3 * Licensed under the Apache License, Version 2.0 (the "License"); 4 * you may not use this file except in compliance with the License. 5 * You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software 10 * distributed under the License is distributed on an "AS IS" BASIS, 11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 * See the License for the specific language governing permissions and 13 * limitations under the License. 14 */ 15 16 /** 17 * @addtogroup Ffrt 18 * @{ 19 * 20 * @brief ffrt provides APIs. 21 * 22 * 23 * @syscap SystemCapability.Resourceschedule.Ffrt.Core 24 * 25 * @since 10 26 */ 27 28 /** 29 * @file condition_variable.h 30 * 31 * @brief Declares the condition variable interfaces in C. 32 * 33 * @syscap SystemCapability.Resourceschedule.Ffrt.Core 34 * @since 10 35 * @version 1.0 36 */ 37 #ifndef FFRT_API_C_CONDITION_VARIABLE_H 38 #define FFRT_API_C_CONDITION_VARIABLE_H 39 #include <time.h> 40 #include "type_def.h" 41 42 /** 43 * @brief Initializes a condition variable. 44 * 45 * @param cond Indicates a pointer to the condition variable. 46 * @param attr Indicates a pointer to the condition variable attribute. 47 * @return Returns <b>ffrt_thrd_success</b> if the condition variable is initialized; 48 returns <b>ffrt_thrd_error</b> otherwise. 49 * @syscap SystemCapability.Resourceschedule.Ffrt.Core 50 * @since 10 51 * @version 1.0 52 */ 53 FFRT_C_API int ffrt_cond_init(ffrt_cond_t* cond, const ffrt_condattr_t* attr); 54 55 /** 56 * @brief Unblocks at least one of the threads that are blocked on a condition variable. 57 * 58 * @param cond Indicates a pointer to the condition variable. 59 * @return Returns <b>ffrt_thrd_success</b> if the thread is unblocked; 60 returns <b>ffrt_thrd_error</b> otherwise. 61 * @syscap SystemCapability.Resourceschedule.Ffrt.Core 62 * @since 10 63 * @version 1.0 64 */ 65 FFRT_C_API int ffrt_cond_signal(ffrt_cond_t* cond); 66 67 /** 68 * @brief Unblocks all threads currently blocked on a condition variable. 69 * 70 * @param cond Indicates a pointer to the condition variable. 71 * @return Returns <b>ffrt_thrd_success</b> if the threads are unblocked; 72 returns <b>ffrt_thrd_error</b> otherwise. 73 * @syscap SystemCapability.Resourceschedule.Ffrt.Core 74 * @since 10 75 * @version 1.0 76 */ 77 FFRT_C_API int ffrt_cond_broadcast(ffrt_cond_t* cond); 78 79 /** 80 * @brief Blocks the calling thread. 81 * 82 * @param cond Indicates a pointer to the condition variable. 83 * @param mutex Indicates a pointer to the mutex. 84 * @return Returns <b>ffrt_thrd_success</b> if the thread is unblocked after being blocked; 85 returns <b>ffrt_thrd_error</b> otherwise. 86 * @syscap SystemCapability.Resourceschedule.Ffrt.Core 87 * @since 10 88 * @version 1.0 89 */ 90 FFRT_C_API int ffrt_cond_wait(ffrt_cond_t* cond, ffrt_mutex_t* mutex); 91 92 /** 93 * @brief Blocks the calling thread for a given duration. 94 * 95 * @param cond Indicates a pointer to the condition variable. 96 * @param mutex Indicates a pointer to the mutex. 97 * @param time_point Indicates the maximum duration that the thread is blocked. 98 * If <b>ffrt_cond_signal</b> or <b>ffrt_cond_broadcast</b> is not called to unblock the thread 99 * when the maximum duration reaches, the thread is automatically unblocked. 100 * @return Returns <b>ffrt_thrd_success</b> if the thread is unblocked after being blocked; 101 returns <b>ffrt_thrd_timedout</b> if the maximum duration reaches; 102 returns <b>ffrt_thrd_error</b> if the blocking fails. 103 * @since 10 104 * @version 1.0 105 */ 106 FFRT_C_API int ffrt_cond_timedwait(ffrt_cond_t* cond, ffrt_mutex_t* mutex, const struct timespec* time_point); 107 108 /** 109 * @brief Destroys a condition variable. 110 * 111 * @param cond Indicates a pointer to the condition variable. 112 * @return Returns <b>ffrt_thrd_success</b> if the condition variable is destroyed; 113 returns <b>ffrt_thrd_error</b> otherwise. 114 * @since 10 115 * @version 1.0 116 */ 117 FFRT_C_API int ffrt_cond_destroy(ffrt_cond_t* cond); 118 #endif 119