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 Provides FFRT C APIs. 21 * 22 * @since 10 23 */ 24 25 /** 26 * @file condition_variable.h 27 * 28 * @brief Declares the condition variable interfaces in C. 29 * 30 * @library libffrt.z.so 31 * @kit FunctionFlowRuntimeKit 32 * @syscap SystemCapability.Resourceschedule.Ffrt.Core 33 * @since 10 34 * @version 1.0 35 */ 36 37 #ifndef FFRT_API_C_CONDITION_VARIABLE_H 38 #define FFRT_API_C_CONDITION_VARIABLE_H 39 40 #include <time.h> 41 #include "type_def.h" 42 43 /** 44 * @brief Initializes a condition variable. 45 * 46 * @param cond Indicates a pointer to the condition variable. 47 * @param attr Indicates a pointer to the condition variable attribute. 48 * @return Returns <b>ffrt_success</b> if the condition variable is initialized; 49 returns <b>ffrt_error_inval</b> otherwise. 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_success</b> if the thread is unblocked; 60 returns <b>ffrt_error_inval</b> otherwise. 61 * @since 10 62 * @version 1.0 63 */ 64 FFRT_C_API int ffrt_cond_signal(ffrt_cond_t* cond); 65 66 /** 67 * @brief Unblocks all threads currently blocked on a condition variable. 68 * 69 * @param cond Indicates a pointer to the condition variable. 70 * @return Returns <b>ffrt_success</b> if the threads are unblocked; 71 returns <b>ffrt_error_inval</b> otherwise. 72 * @since 10 73 * @version 1.0 74 */ 75 FFRT_C_API int ffrt_cond_broadcast(ffrt_cond_t* cond); 76 77 /** 78 * @brief Blocks the calling thread. 79 * 80 * @param cond Indicates a pointer to the condition variable. 81 * @param mutex Indicates a pointer to the mutex. 82 * @return Returns <b>ffrt_success</b> if the thread is unblocked after being blocked; 83 returns <b>ffrt_error_inval</b> otherwise. 84 * @since 10 85 * @version 1.0 86 */ 87 FFRT_C_API int ffrt_cond_wait(ffrt_cond_t* cond, ffrt_mutex_t* mutex); 88 89 /** 90 * @brief Blocks the calling thread for a given duration. 91 * 92 * If <b>ffrt_cond_signal</b> or <b>ffrt_cond_broadcast</b> is not called to unblock the thread 93 * when the maximum duration reaches, the thread is automatically unblocked. 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 * @return Returns <b>ffrt_success</b> if the thread is unblocked after being blocked; 99 returns <b>ffrt_error_timedout</b> if the maximum duration reaches; 100 returns <b>ffrt_error_inval</b> if the blocking fails. 101 * @since 10 102 * @version 1.0 103 */ 104 FFRT_C_API int ffrt_cond_timedwait(ffrt_cond_t* cond, ffrt_mutex_t* mutex, const struct timespec* time_point); 105 106 /** 107 * @brief Destroys a condition variable, the user needs to invoke this interface. 108 * 109 * @param cond Indicates a pointer to the condition variable. 110 * @return Returns <b>ffrt_success</b> if the condition variable is destroyed; 111 returns <b>ffrt_error_inval</b> otherwise. 112 * @since 10 113 * @version 1.0 114 */ 115 FFRT_C_API int ffrt_cond_destroy(ffrt_cond_t* cond); 116 117 #endif // FFRT_API_C_CONDITION_VARIABLE_H 118 /** @} */