1e41f4b71Sopenharmony_ci# condition_variable.h 2e41f4b71Sopenharmony_ci 3e41f4b71Sopenharmony_ci 4e41f4b71Sopenharmony_ci## Overview 5e41f4b71Sopenharmony_ci 6e41f4b71Sopenharmony_ciThe **condition_variable.h** file declares the condition variable interfaces in C. 7e41f4b71Sopenharmony_ci 8e41f4b71Sopenharmony_ci**Since**: 10 9e41f4b71Sopenharmony_ci 10e41f4b71Sopenharmony_ci**Related module**: [FFRT](_f_f_r_t.md) 11e41f4b71Sopenharmony_ci 12e41f4b71Sopenharmony_ci 13e41f4b71Sopenharmony_ci## Summary 14e41f4b71Sopenharmony_ci 15e41f4b71Sopenharmony_ci 16e41f4b71Sopenharmony_ci### Functions 17e41f4b71Sopenharmony_ci 18e41f4b71Sopenharmony_ci| Name| Description| 19e41f4b71Sopenharmony_ci| -------- | -------- | 20e41f4b71Sopenharmony_ci| FFRT_C_API int [ffrt_cond_init](_f_f_r_t.md#ffrt_cond_init) ([ffrt_cond_t](ffrt__cond__t.md)\* cond, const [ffrt_condattr_t](ffrt__condattr__t.md)\* attr) | Initializes a condition variable. | 21e41f4b71Sopenharmony_ci| FFRT_C_API int [ffrt_cond_signal](_f_f_r_t.md#ffrt_cond_signal) ([ffrt_cond_t](ffrt__cond__t.md)\* cond) | Unblocks at least one of the threads that are blocked on a condition variable. | 22e41f4b71Sopenharmony_ci| FFRT_C_API int [ffrt_cond_broadcast](_f_f_r_t.md#ffrt_cond_broadcast) ([ffrt_cond_t](ffrt__cond__t.md)\* cond) | Unblocks all threads currently blocked on a condition variable. | 23e41f4b71Sopenharmony_ci| FFRT_C_API int [ffrt_cond_wait](_f_f_r_t.md#ffrt_cond_wait) ([ffrt_cond_t](ffrt__cond__t.md)\* cond, [ffrt_mutex_t](ffrt__mutex__t.md)\* mutex) | Blocks the calling thread on a condition variable. | 24e41f4b71Sopenharmony_ci| FFRT_C_API int [ffrt_cond_timedwait](_f_f_r_t.md#ffrt_cond_timedwait) ([ffrt_cond_t](ffrt__cond__t.md)\* cond, [ffrt_mutex_t](ffrt__mutex__t.md)\* mutex, const struct timespec\* time_point) | Blocks the calling thread on a condition variable for a given duration. | 25e41f4b71Sopenharmony_ci| FFRT_C_API int [ffrt_cond_destroy](_f_f_r_t.md#ffrt_cond_destroy) ([ffrt_cond_t](ffrt__cond__t.md)\* cond) | Destroys a condition variable. | 26