Device hotplug event notification

This page details how to use the libusb hotplug interface. More...

Typedefs
typedef int	libusb_hotplug_callback_handle
	Callback handle.
typedef int(*	libusb_hotplug_callback_fn )(libusb_context *ctx, libusb_device *device, libusb_hotplug_event event, void *user_data)
	Hotplug callback function type.

Enumerations
enum	libusb_hotplug_flag { LIBUSB_HOTPLUG_ENUMERATE = 1 }
	Flags for hotplug events. More...
enum	libusb_hotplug_event { LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED = 0x01, LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT = 0x02 }
	Hotplug events. More...
enum	{ LIBUSB_HOTPLUG_CLASS_ANY = -1, LIBUSB_HOTPLUG_VENDORID_ANY = -2, LIBUSB_HOTPLUG_PRODUCTID_ANY = -3 }
	Wildcard matching for hotplug events. More...

Functions
int	libusb_hotplug_register_callback (libusb_context *ctx, libusb_hotplug_event events, libusb_hotplug_flag flags, int vendor_id, int product_id, int dev_class, libusb_hotplug_callback_fn cb_fn, void *user_data, libusb_hotplug_callback_handle *handle)
	Register a hotplug callback function.
void	libusb_hotplug_deregister_callback (libusb_context *ctx, libusb_hotplug_callback_handle handle)
	Deregisters a hotplug callback.

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Detailed Description

This page details how to use the libusb hotplug interface.

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Typedef Documentation

typedef int libusb_hotplug_callback_handle

Callback handle.

Callbacks handles are generated by libusb_hotplug_register_callback() and returned by libusb_hotplug_deregister_callback() or returning 1 from the callback function.

For more information, see Device hotplug event notification.

typedef int( * libusb_hotplug_callback_fn)(libusb_context *ctx, libusb_device *device, libusb_hotplug_event event, void *user_data)

Hotplug callback function type.

When requesting hotplug support, you pass a pointer to a callback function of this type. This callback may be called by an internal event thread and as such should do minimal processing before returning. libusb will call this function later, when a matching device has been connected. See Device hotplug event notification for more information.

Parameters:

libusb_context	context of this notification
device	libusb_device this event occurred on
event	event that occurred
user_data	user data provided when this callback was registered

Returns:

bool whether this callback is finished processing events. returning 1 will cause this callback to be deregistered

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Enumeration Type Documentation

enum libusb_hotplug_flag

Flags for hotplug events.

Enumerator:

LIBUSB_HOTPLUG_ENUMERATE

Arm the callback and fire it for all matching attached devices.

enum libusb_hotplug_event

Hotplug events.

Enumerator:

LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED	A device has been plugged in and is ready to use.
LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT	A device has left and is no longer available. It is the user's responsibility to call libusb_close on any handle associated with a disconnected device. It is safe to call libusb_get_device_descriptor on a device that has left

anonymous enum

Wildcard matching for hotplug events.

Enumerator:

LIBUSB_HOTPLUG_CLASS_ANY	Match any device class.
LIBUSB_HOTPLUG_VENDORID_ANY	Match any vendor id.
LIBUSB_HOTPLUG_PRODUCTID_ANY	Match any product id.

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Function Documentation

int libusb_hotplug_register_callback	(	libusb_context *	ctx,
		libusb_hotplug_event	events,
		libusb_hotplug_flag	flags,
		int	vendor_id,
		int	product_id,
		int	dev_class,
		libusb_hotplug_callback_fn	cb_fn,
		void *	user_data,
		libusb_hotplug_callback_handle *	handle
	)

Register a hotplug callback function.

Parameters:

[in]	ctx	context to register this callback with
[in]	events	the events that will trigger this callback
[in]	flags	hotplug callback flags (described above)
[in]	vendor_id	the vendor id to match or LIBUSB_HOTPLUG_PRODUCTID_ANY
[in]	product_id	the product id to match or LIBUSB_HOTPLUG_PRODUCTID_ANY
[in]	dev_class	the device class to match or LIBUSB_HOTPLUG_CLASS_ANY
[in]	cb_fn	the function to be invoked on a matching event/device
[in]	user_data	user data to pass to the callback function
[out]	handle	pointer to store the handle of the allocated callback (can be NULL)

Returns:

LIBUSB_SUCCESS on success LIBUSB_ERROR code on failure

void libusb_hotplug_deregister_callback	(	libusb_context *	ctx,
		libusb_hotplug_callback_handle	handle
	)

Deregisters a hotplug callback.

Do not call this function from within a callback function. This will result in deadlock.

Parameters:

[in]	ctx	context this callback is registered with
[in]	handle	the handle of the callback to deregister