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53 lines
1.5 KiB
Text
53 lines
1.5 KiB
Text
libevdev_get_num_slots(3)
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=========================
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NAME
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----
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libevdev_get_num_slots, libevdev_get_current_slot - get the number of available multitouch slots and the currently active slot
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SYNOPSIS
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--------
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#include <libevdev/libevdev.h>
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int libevdev_get_num_slots(const struct libevdev *dev);
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int libevdev_get_current_slot(const struct libevdev *dev);
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DESCRIPTION
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-----------
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*libevdev_get_num_slots* returns the available number of multitouch slots on
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this device.
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*libevdev_get_current_slot* returns the currently active slot. Note that
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this value may lag behind the state visible to other readers on the
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same device. The return value of this function is the current slot as seen
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by the caller, i.e. the state as defined by the set of events processed so
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far.
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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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RETURN VALUE
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------------
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On success, *libevdev_get_num_slots* returns the number of slots. If the
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device does not support the slot protocol, -1 is returned.
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On success, *libevdev_get_current_slot* returns the current of slot ID. If
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the device does not support the slot protocol, the return value is
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undefined.
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NOTES
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-----
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Some devices support more touch points that they expose multitouch slots
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for. For example, a touchpad may only expose two slots, but detect up to
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four-finger touches. A caller should check for BTN_TOOL_TRIPLETAP,
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BTN_TOOL_QUADTAP, etc. as well as the state of the slots.
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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_slot_value(3)
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