libevdev_get_event_value(3)
===========================

NAME
----

libevdev_get_event_value, libevdev_fetch_event_value, libevdev_get_slot_value, libevdev_fetch_slot_value - retrieve the current value of an event type and code.

SYNOPSIS
--------

#include <libevdev/libevdev.h>

int libevdev_get_event_value(const struct libevdev *dev, unsigned int type, unsigned int code);
int libevdev_fetch_event_value(const struct libevdev *dev, unsigned int type, unsigned int code, int *value);
int libevdev_get_slot_value(const struct libevdev *dev, unsigned int slot, unsigned int code);
int libevdev_fetch_slot_value(const struct libevdev *dev, unsigned int slot, unsigned int code, int *value);

DESCRIPTION
-----------
*libevdev_get_event_value* returns the current value of the given event type
and code on this device. The caller must check if the event type and code
are available on this device with *libevdev_has_event_type(3)* and
*libevdev_has_event_code(3)*.

*libevdev_get_event_value* may not be used to check for the current value
of any ABS_MT_* axis if the device supports multitouchs slots. Use
*libevdev_get_slot_value* instead.

*libevev_get_slot_value* returns the current value of the given multitouch
slot. The caller must check if the device supports the multitouch slot
protocol with *libevdev_has_event_type(3)* and
*libevdev_has_event_code(3)*. The caller must ensure that the requested slot
value is within the allowed range (see *libevdev_get_num_slots(3)*).

*libevdev_fetch_event_value* and *libevdev_fetch_slot_value* are convenience
functions so callers can check if an axis or slot exists and fetch the value
in one function call.

PARAMETERS
----------
*dev*::
	Pointer to the libevdev device.

*type*::
	Specifies the event type to query.

*code*::
	Specifies the event code to query.

*slot*::
	Specifies the MT slot to query.

*value*::
	Returns the current value of the event code or slot.

RETURN VALUE
------------
On success, *libevdev_get_event_value* and *libevdev_get_slot_value* returns
the current value of the axis and/or slot. If the device does not support
this axis or the slot is invalid, the return value is undefined.

On success, *libevdev_fetch_event_value* and *libevdev_fetch_slot_value*
return 1 and ''value'' is set to the current value of this axis, or slot,
respectively. If the device does not support this axis or the slot is
invalid, 0 is returned and ''value'' is left as-is.

SEE ALSO
--------

libevdev_has_event_type(3), libevdev_has_event_code(3), libevdev_get_num_slots(3)