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71 lines
2.5 KiB
Text
71 lines
2.5 KiB
Text
libevdev_get_event_value(3)
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===========================
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NAME
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----
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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.
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SYNOPSIS
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--------
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#include <libevdev/libevdev.h>
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int libevdev_get_event_value(const struct libevdev *dev, unsigned int type, unsigned int code);
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int libevdev_fetch_event_value(const struct libevdev *dev, unsigned int type, unsigned int code, int *value);
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int libevdev_get_slot_value(const struct libevdev *dev, unsigned int slot, unsigned int code);
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int libevdev_fetch_slot_value(const struct libevdev *dev, unsigned int slot, unsigned int code, int *value);
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DESCRIPTION
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-----------
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*libevdev_get_event_value* returns the current value of the given event type
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and code on this device. The caller must check if the event type and code
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are available on this device with *libevdev_has_event_type(3)* and
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*libevdev_has_event_code(3)*.
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*libevdev_get_event_value* may not be used to check for the current value
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of any ABS_MT_* axis if the device supports multitouchs slots. Use
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*libevdev_get_slot_value* instead.
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*libevev_get_slot_value* returns the current value of the given multitouch
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slot. The caller must check if the device supports the multitouch slot
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protocol with *libevdev_has_event_type(3)* and
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*libevdev_has_event_code(3)*. The caller must ensure that the requested slot
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value is within the allowed range (see *libevdev_get_num_slots(3)*).
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*libevdev_fetch_event_value* and *libevdev_fetch_slot_value* are convenience
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functions so callers can check if an axis or slot exists and fetch the value
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in one function call.
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PARAMETERS
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----------
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*dev*::
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Pointer to the libevdev device.
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*type*::
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Specifies the event type to query.
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*code*::
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Specifies the event code to query.
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*slot*::
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Specifies the MT slot to query.
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*value*::
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Returns the current value of the event code or slot.
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RETURN VALUE
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------------
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On success, *libevdev_get_event_value* and *libevdev_get_slot_value* returns
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the current value of the axis and/or slot. If the device does not support
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this axis or the slot is invalid, the return value is undefined.
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On success, *libevdev_fetch_event_value* and *libevdev_fetch_slot_value*
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return 1 and ''value'' is set to the current value of this axis, or slot,
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respectively. If the device does not support this axis or the slot is
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invalid, 0 is returned and ''value'' is left as-is.
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SEE ALSO
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--------
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libevdev_has_event_type(3), libevdev_has_event_code(3), libevdev_get_num_slots(3)
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