1# usb_ddk_api.h
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3
4## Overview
5
6Declares the USB DDK APIs used by the USB host to access USB devices.
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8**Since**
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1010
11
12**Related Modules**
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14[USB DDK](_usb_ddk.md)
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16
17## Summary
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19
20### Functions
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22| Name| Description|
23| -------- | -------- |
24| [OH_Usb_Init](_usb_ddk.md#oh_usb_init) (void) | Initializes the DDK.|
25| [OH_Usb_Release](_usb_ddk.md#oh_usb_release) (void) | Releases the USB DDK.|
26| [OH_Usb_GetDeviceDescriptor](_usb_ddk.md#oh_usb_getdevicedescriptor) (uint64_t deviceId, struct [UsbDeviceDescriptor](_usb_device_descriptor.md) \*desc) | Obtains the device descriptor.|
27| [OH_Usb_GetConfigDescriptor](_usb_ddk.md#oh_usb_getconfigdescriptor) (uint64_t deviceId, uint8_t configIndex, struct [UsbDdkConfigDescriptor](_usb_ddk_config_descriptor.md) \*\*const config) | Obtains the configuration descriptor. To avoid memory leakage, use [OH_Usb_FreeConfigDescriptor()](_usb_ddk.md#oh_usb_freeconfigdescriptor) to release a descriptor after use.|
28| [OH_Usb_FreeConfigDescriptor](_usb_ddk.md#oh_usb_freeconfigdescriptor) (const struct [UsbDdkConfigDescriptor](_usb_ddk_config_descriptor.md) \*const config) | Releases the configuration descriptor. To avoid memory leakage, release a descriptor after use.|
29| [OH_Usb_ClaimInterface](_usb_ddk.md#oh_usb_claiminterface) (uint64_t deviceId, uint8_t interfaceIndex, uint64_t \*[interfaceHandle](usb__ddk__types_8h.md#interfacehandle)) | Declares a USB interface.|
30| [OH_Usb_ReleaseInterface](_usb_ddk.md#oh_usb_releaseinterface) (uint64_t [interfaceHandle](usb__ddk__types_8h.md#interfacehandle)) | Releases a USB interface.|
31| [OH_Usb_SelectInterfaceSetting](_usb_ddk.md#oh_usb_selectinterfacesetting) (uint64_t [interfaceHandle](usb__ddk__types_8h.md#interfacehandle), uint8_t settingIndex) | Activates the alternate setting of a USB interface.|
32| [OH_Usb_GetCurrentInterfaceSetting](_usb_ddk.md#oh_usb_getcurrentinterfacesetting) (uint64_t [interfaceHandle](usb__ddk__types_8h.md#interfacehandle), uint8_t \*settingIndex) | Obtains the activated alternate setting of a USB interface.|
33| [OH_Usb_SendControlReadRequest](_usb_ddk.md#oh_usb_sendcontrolreadrequest) (uint64_t [interfaceHandle](usb__ddk__types_8h.md#interfacehandle), const struct [UsbControlRequestSetup](_usb_control_request_setup.md) \*setup, uint32_t [timeout](usb__ddk__types_8h.md#timeout), uint8_t \*data, uint32_t \*dataLen) | Sends a control read transfer request. This API works in a synchronous manner.|
34| [OH_Usb_SendControlWriteRequest](_usb_ddk.md#oh_usb_sendcontrolwriterequest) (uint64_t [interfaceHandle](usb__ddk__types_8h.md#interfacehandle), const struct [UsbControlRequestSetup](_usb_control_request_setup.md) \*setup, uint32_t [timeout](usb__ddk__types_8h.md#timeout), const uint8_t \*data, uint32_t dataLen) | Sends a control write transfer request. This API works in a synchronous manner.|
35| [OH_Usb_SendPipeRequest](_usb_ddk.md#oh_usb_sendpiperequest) (const struct [UsbRequestPipe](_usb_request_pipe.md) \*pipe, [UsbDeviceMemMap](_usb_device_mem_map.md) \*devMmap) | Sends a pipe request. This API works in a synchronous manner. It applies to interrupt transfer and bulk transfer.|
36| [OH_Usb_SendPipeRequestWithAshmem](_usb_ddk.md#oh_usb_sendpiperequestwithashmem) (const struct [UsbRequestPipe](_usb_request_pipe.md) \*pipe, [DDK_Ashmem](_ddk_ashmem.md) \*ashmem) | Sends a pipe request for the shared memory. This API returns the result synchronously. It applies to interrupt transfer and bulk transfer.|
37| [OH_Usb_CreateDeviceMemMap](_usb_ddk.md#oh_usb_createdevicememmap) (uint64_t deviceId, size_t size, [UsbDeviceMemMap](_usb_device_mem_map.md) \*\*devMmap) | Creates a buffer. To avoid memory leakage, use [OH_Usb_DestroyDeviceMemMap()](_usb_ddk.md#oh_usb_destroydevicememmap) to destroy a buffer after use.|
38| [OH_Usb_DestroyDeviceMemMap](_usb_ddk.md#oh_usb_destroydevicememmap) ([UsbDeviceMemMap](_usb_device_mem_map.md) \*devMmap) | Destroys a buffer. To avoid resource leakage, destroy a buffer in time after use.|
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