1# sleep.h 2 3<!--Kit: Function Flow Runtime Kit--> 4<!--Subsystem: Resourceschedule--> 5<!--Owner: @chuchihtung; @yanleo--> 6<!--Designer: @geoffrey_guo; @huangyouzhong--> 7<!--Tester: @lotsof; @sunxuhao--> 8<!--Adviser: @foryourself--> 9 10## Overview 11 12The **sleep.h** file declares the sleep and yield APIs in C. 13 14**File to include**: <ffrt/sleep.h> 15 16**Library**: libffrt.z.so 17 18**System capability**: SystemCapability.Resourceschedule.Ffrt.Core 19 20**Since**: 10 21 22**Related module**: [FFRT](capi-ffrt.md) 23 24## Summary 25 26### Function 27 28| Name| Description| 29| -- | -- | 30| [FFRT_C_API int ffrt_usleep(uint64_t usec)](#ffrt_usleep) | Sets the fixed sleep time.| 31| [FFRT_C_API void ffrt_yield(void)](#ffrt_yield) | Passes control to other tasks so that they can be executed.| 32 33## Function Description 34 35### ffrt_usleep() 36 37``` 38FFRT_C_API int ffrt_usleep(uint64_t usec) 39``` 40 41**Description** 42 43Sets the fixed sleep time. 44 45**Since**: 10 46 47 48**Parameters** 49 50| Name| Description| 51| -- | -- | 52| uint64_t usec | Sleep time, in microseconds.| 53 54**Returns** 55 56| Type| Description| 57| -- | -- | 58| FFRT_C_API int | Returns **ffrt_success** if the sleep time is set;<br> returns **ffrt_error** otherwise.| 59 60### ffrt_yield() 61 62``` 63FFRT_C_API void ffrt_yield(void) 64``` 65 66**Description** 67 68Passes control to other tasks so that they can be executed. 69 70**Since**: 10 71