This module provides an API for raw access to USB devices.

Required Header

#include <usb_host.h>

Overview

USB host API provides direct access to USB devices. Applications with user confirmation can get access to external USB devices, which include card readers, NFC readers, printers, and QR code readers. Before using it, become familiar with USB protocol specification. Note that this API is created for *host* mode USB, i.e. communication with connected devices.

Before using any of usb_host API functions you must initialize API context. Also you must cleanup context after using USB host API.

Related Features

This API is related with the following features:

http://tizen.org/feature/usb.host

It is recommended to design feature related codes in your application for reliability.

You can check if a device supports the related features for this API by using System Information, thereby controlling the procedure of your application.

To ensure your application is only running on the device with specific features, please define the features in your manifest file using the manifest editor in the SDK.

More details on featuring your application can be found from Feature List.

Functions
int	usb_host_create (usb_host_context_h *ctx)
	Initializes usb_host context.
int	usb_host_destroy (usb_host_context_h ctx)
	Deinitializes usb_host context.
Typedefs
typedef struct usb_host_context_s *	usb_host_context_h
	Context handle to USB host.

Typedef Documentation

typedef struct usb_host_context_s* usb_host_context_h

Context handle to USB host.

This structure represents usb_host session. Using own session allows to use this API independently. For example calling usb_host_destroy() will not destroy resources that are being used by another user of the library.

To create session there is need to call usb_host_create(), to destroy call usb_host_destroy(). Each session created by usb_host_create() has to be destroyed using usb_host_destroy()

Since :: 3.0

Enumeration Type Documentation

enum usb_host_error_e

Enumeration of error codes reported by USB host API.

Since :: 3.0

Enumerator:

USB_HOST_ERROR_NONE	Successful
USB_HOST_ERROR_IO_ERROR	I/O error
USB_HOST_ERROR_INVALID_PARAMETER	Invalid parameter
USB_HOST_ERROR_PERMISSION_DENIED	Permission denied
USB_HOST_ERROR_NO_SUCH_DEVICE	No device
USB_HOST_ERROR_NOT_FOUND	Entity not found
USB_HOST_ERROR_RESOURCE_BUSY	Resource busy
USB_HOST_ERROR_TIMED_OUT	Operation timed out
USB_HOST_ERROR_OVERFLOW	Overflow
USB_HOST_ERROR_DEVICE_NOT_OPENED	Device is not opened
USB_HOST_ERROR_BROKEN_PIPE	Pipe error
USB_HOST_ERROR_INTERRUPTED_SYS_CALL	System call interrupted
USB_HOST_ERROR_OUT_OF_MEMORY	Insufficient memory
USB_HOST_ERROR_NOT_SUPPORTED	Operation not supported
USB_HOST_ERROR_UNKNOWN	Other error

Function Documentation

int usb_host_create ( usb_host_context_h * ctx )

Initializes usb_host context.

This function must be called before any other function from this module.

Since :: 3.0

Remarks:: ctx should be destroyed by calling usb_host_destroy() when no longer needed.

Parameters:

[out] ctx Context pointer

Returns:: 0 on success, otherwise a negative error value

Return values:

USB_HOST_ERROR_OUT_OF_MEMORY	Out of memory
USB_HOST_ERROR_INVALID_PARAMETER	Invalid parameter was passed
USB_HOST_ERROR_NONE	Successful

Postcondition:: usb_host_destroy() should be called to free resources allocated for ctx by this function.

int usb_host_destroy ( usb_host_context_h ctx )

Deinitializes usb_host context.

This function must be called after closing all devices and before application close. It has to be called to clean the memory used by library.

Since :: 3.0