libevdev  1.4
A wrapper library for evdev devices
Enumerations | Functions
Modifying the appearance or capabilities of the device

Modifying the set of events reported by this device. More...

Enumerations

enum  libevdev_led_value { LIBEVDEV_LED_ON, LIBEVDEV_LED_OFF }
 

Functions

void libevdev_set_name (struct libevdev *dev, const char *name)
 Change the device's name as returned by libevdev_get_name(). More...
 
void libevdev_set_phys (struct libevdev *dev, const char *phys)
 Change the device's physical location as returned by libevdev_get_phys(). More...
 
void libevdev_set_uniq (struct libevdev *dev, const char *uniq)
 Change the device's unique identifier as returned by libevdev_get_uniq(). More...
 
void libevdev_set_id_product (struct libevdev *dev, int product_id)
 
void libevdev_set_id_vendor (struct libevdev *dev, int vendor_id)
 
void libevdev_set_id_bustype (struct libevdev *dev, int bustype)
 
void libevdev_set_id_version (struct libevdev *dev, int version)
 
int libevdev_enable_property (struct libevdev *dev, unsigned int prop)
 
int libevdev_set_event_value (struct libevdev *dev, unsigned int type, unsigned int code, int value)
 Set the value for a given event type and code. More...
 
int libevdev_set_slot_value (struct libevdev *dev, unsigned int slot, unsigned int code, int value)
 Set the value for a given code for the given slot. More...
 
void libevdev_set_abs_minimum (struct libevdev *dev, unsigned int code, int min)
 Change the minimum for the given EV_ABS event code, if the code exists. More...
 
void libevdev_set_abs_maximum (struct libevdev *dev, unsigned int code, int max)
 Change the maximum for the given EV_ABS event code, if the code exists. More...
 
void libevdev_set_abs_fuzz (struct libevdev *dev, unsigned int code, int fuzz)
 Change the fuzz for the given EV_ABS event code, if the code exists. More...
 
void libevdev_set_abs_flat (struct libevdev *dev, unsigned int code, int flat)
 Change the flat for the given EV_ABS event code, if the code exists. More...
 
void libevdev_set_abs_resolution (struct libevdev *dev, unsigned int code, int resolution)
 Change the resolution for the given EV_ABS event code, if the code exists. More...
 
void libevdev_set_abs_info (struct libevdev *dev, unsigned int code, const struct input_absinfo *abs)
 Change the abs info for the given EV_ABS event code, if the code exists. More...
 
int libevdev_enable_event_type (struct libevdev *dev, unsigned int type)
 Forcibly enable an event type on this device, even if the underlying device does not support it. More...
 
int libevdev_disable_event_type (struct libevdev *dev, unsigned int type)
 Forcibly disable an event type on this device, even if the underlying device provides it. More...
 
int libevdev_enable_event_code (struct libevdev *dev, unsigned int type, unsigned int code, const void *data)
 Forcibly enable an event code on this device, even if the underlying device does not support it. More...
 
int libevdev_disable_event_code (struct libevdev *dev, unsigned int type, unsigned int code)
 Forcibly disable an event code on this device, even if the underlying device provides it. More...
 
int libevdev_kernel_set_abs_info (struct libevdev *dev, unsigned int code, const struct input_absinfo *abs)
 Set the device's EV_ABS axis to the value defined in the abs parameter. More...
 
int libevdev_kernel_set_led_value (struct libevdev *dev, unsigned int code, enum libevdev_led_value value)
 Turn an LED on or off. More...
 
int libevdev_kernel_set_led_values (struct libevdev *dev,...)
 Turn multiple LEDs on or off simultaneously. More...
 
int libevdev_set_clock_id (struct libevdev *dev, int clockid)
 Set the clock ID to be used for timestamps. More...
 

Detailed Description

Modifying the set of events reported by this device.

By default, the libevdev device mirrors the kernel device, enabling only those bits exported by the kernel. This set of functions enable or disable bits as seen from the caller.

Enabling an event type or code does not affect event reporting - a software-enabled event will not be generated by the physical hardware. Disabling an event will prevent libevdev from routing such events to the caller. Enabling and disabling event types and codes is at the library level and thus only affects the caller.

If an event type or code is enabled at kernel-level, future users of this device will see this event enabled. Currently there is no option of disabling an event type or code at kernel-level.

Enumeration Type Documentation

Enumerator
LIBEVDEV_LED_ON 

Turn the LED on.

LIBEVDEV_LED_OFF 

Turn the LED off.

Function Documentation

int libevdev_disable_event_code ( struct libevdev *  dev,
unsigned int  type,
unsigned int  code 
)

Forcibly disable an event code on this device, even if the underlying device provides it.

This effectively mutes the respective set of events. libevdev will filter any events matching this type and code and none will reach the caller. libevdev_has_event_code() will return false for this code.

Disabling all event codes for a given type will not disable the event type. Use libevdev_disable_event_type() for that.

This is a local modification only affecting only this representation of this device.

Disabling codes of type EV_SYN will not work. Don't shoot yourself in the foot. It hurts.

Parameters
devThe evdev device, already initialized with libevdev_set_fd()
typeThe event type to disable (EV_ABS, EV_KEY, ...)
codeThe event code to disable (ABS_X, REL_X, etc.)
Returns
0 on success or -1 otherwise
See also
libevdev_has_event_code
libevdev_disable_event_type
int libevdev_disable_event_type ( struct libevdev *  dev,
unsigned int  type 
)

Forcibly disable an event type on this device, even if the underlying device provides it.

This effectively mutes the respective set of events. libevdev will filter any events matching this type and none will reach the caller. libevdev_has_event_type() will return false for this type.

In most cases, a caller likely only wants to disable a single code, not the whole type. Use libevdev_disable_event_code() for that.

Disabling EV_SYN will not work. Don't shoot yourself in the foot. It hurts.

This is a local modification only affecting only this representation of this device.

Parameters
devThe evdev device, already initialized with libevdev_set_fd()
typeThe event type to disable (EV_ABS, EV_KEY, ...)
Returns
0 on success or -1 otherwise
See also
libevdev_has_event_type
libevdev_disable_event_type
int libevdev_enable_event_code ( struct libevdev *  dev,
unsigned int  type,
unsigned int  code,
const void *  data 
)

Forcibly enable an event code on this device, even if the underlying device does not support it.

While this cannot make the device actually report such events, it will now return true for libevdev_has_event_code().

The last argument depends on the type and code:

  • If type is EV_ABS, data must be a pointer to a struct input_absinfo containing the data for this axis.
  • If type is EV_REP, daat must be a pointer to a int containing the data for this axis
  • For all other types, the argument must be NULL.

This function calls libevdev_enable_event_type() if necessary.

This is a local modification only affecting only this representation of this device.

If this function is called with a type of EV_ABS and EV_REP on a device that already has the given event code enabled, the values in data overwrite the previous values.

Parameters
devThe evdev device, already initialized with libevdev_set_fd()
typeThe event type to enable (EV_ABS, EV_KEY, ...)
codeThe event code to enable (ABS_X, REL_X, etc.)
dataIf type is EV_ABS, data points to a struct input_absinfo. If type is EV_REP, data points to an integer. Otherwise, data must be NULL.
Returns
0 on success or -1 otherwise
See also
libevdev_enable_event_type
int libevdev_enable_event_type ( struct libevdev *  dev,
unsigned int  type 
)

Forcibly enable an event type on this device, even if the underlying device does not support it.

While this cannot make the device actually report such events, it will now return true for libevdev_has_event_type().

This is a local modification only affecting only this representation of this device.

Parameters
devThe evdev device, already initialized with libevdev_set_fd()
typeThe event type to enable (EV_ABS, EV_KEY, ...)
Returns
0 on success or -1 otherwise
See also
libevdev_has_event_type
int libevdev_enable_property ( struct libevdev *  dev,
unsigned int  prop 
)
Parameters
devThe evdev device
propThe input property to enable, one of INPUT_PROP_...
Returns
0 on success or -1 on failure
Note
This function may be called before libevdev_set_fd(). A call to libevdev_set_fd() will overwrite any previously set value.
int libevdev_kernel_set_abs_info ( struct libevdev *  dev,
unsigned int  code,
const struct input_absinfo *  abs 
)

Set the device's EV_ABS axis to the value defined in the abs parameter.

This will be written to the kernel.

Parameters
devThe evdev device, already initialized with libevdev_set_fd()
codeThe EV_ABS event code to modify, one of ABS_X, ABS_Y, etc.
absAxis info to set the kernel axis to
Returns
0 on success, or a negative errno on failure
See also
libevdev_enable_event_code
int libevdev_kernel_set_led_value ( struct libevdev *  dev,
unsigned int  code,
enum libevdev_led_value  value 
)

Turn an LED on or off.

Convenience function, if you need to modify multiple LEDs simultaneously, use libevdev_kernel_set_led_values() instead.

Note
enabling an LED requires write permissions on the device's file descriptor.
Parameters
devThe evdev device, already initialized with libevdev_set_fd()
codeThe EV_LED event code to modify, one of LED_NUML, LED_CAPSL, ...
valueSpecifies whether to turn the LED on or off
Returns
0 on success, or a negative errno on failure
int libevdev_kernel_set_led_values ( struct libevdev *  dev,
  ... 
)

Turn multiple LEDs on or off simultaneously.

This function expects a pair of LED codes and values to set them to, terminated by a -1. For example, to switch the NumLock LED on but the CapsLock LED off, use:

1 libevdev_kernel_set_led_values(dev, LED_NUML, LIBEVDEV_LED_ON,
2  LED_CAPSL, LIBEVDEV_LED_OFF,
3  -1);

If any LED code or value is invalid, this function returns -EINVAL and no LEDs are modified.

Note
enabling an LED requires write permissions on the device's file descriptor.
Parameters
devThe evdev device, already initialized with libevdev_set_fd()
...A pair of LED_* event codes and libevdev_led_value_t, followed by -1 to terminate the list.
Returns
0 on success, or a negative errno on failure
void libevdev_set_abs_flat ( struct libevdev *  dev,
unsigned int  code,
int  flat 
)

Change the flat for the given EV_ABS event code, if the code exists.

This function has no effect if libevdev_has_event_code() returns false for this code.

Parameters
devThe evdev device, already initialized with libevdev_set_fd()
codeOne of ABS_X, ABS_Y, ...
flatThe new flat for this axis
void libevdev_set_abs_fuzz ( struct libevdev *  dev,
unsigned int  code,
int  fuzz 
)

Change the fuzz for the given EV_ABS event code, if the code exists.

This function has no effect if libevdev_has_event_code() returns false for this code.

Parameters
devThe evdev device, already initialized with libevdev_set_fd()
codeOne of ABS_X, ABS_Y, ...
fuzzThe new fuzz for this axis
void libevdev_set_abs_info ( struct libevdev *  dev,
unsigned int  code,
const struct input_absinfo *  abs 
)

Change the abs info for the given EV_ABS event code, if the code exists.

This function has no effect if libevdev_has_event_code() returns false for this code.

Parameters
devThe evdev device, already initialized with libevdev_set_fd()
codeOne of ABS_X, ABS_Y, ...
absThe new absolute axis data (min, max, fuzz, flat, resolution)
void libevdev_set_abs_maximum ( struct libevdev *  dev,
unsigned int  code,
int  max 
)

Change the maximum for the given EV_ABS event code, if the code exists.

This function has no effect if libevdev_has_event_code() returns false for this code.

Parameters
devThe evdev device, already initialized with libevdev_set_fd()
codeOne of ABS_X, ABS_Y, ...
maxThe new maxium for this axis
void libevdev_set_abs_minimum ( struct libevdev *  dev,
unsigned int  code,
int  min 
)

Change the minimum for the given EV_ABS event code, if the code exists.

This function has no effect if libevdev_has_event_code() returns false for this code.

Parameters
devThe evdev device, already initialized with libevdev_set_fd()
codeOne of ABS_X, ABS_Y, ...
minThe new minimum for this axis
void libevdev_set_abs_resolution ( struct libevdev *  dev,
unsigned int  code,
int  resolution 
)

Change the resolution for the given EV_ABS event code, if the code exists.

This function has no effect if libevdev_has_event_code() returns false for this code.

Parameters
devThe evdev device, already initialized with libevdev_set_fd()
codeOne of ABS_X, ABS_Y, ...
resolutionThe new axis resolution
int libevdev_set_clock_id ( struct libevdev *  dev,
int  clockid 
)

Set the clock ID to be used for timestamps.

Further events from this device will report an event time based on the given clock.

This is a modification only affecting this representation of this device.

Parameters
devThe evdev device, already initialized with libevdev_set_fd()
clockidThe clock to use for future events. Permitted values are CLOCK_MONOTONIC and CLOCK_REALTIME (the default).
Returns
0 on success, or a negative errno on failure
int libevdev_set_event_value ( struct libevdev *  dev,
unsigned int  type,
unsigned int  code,
int  value 
)

Set the value for a given event type and code.

This only makes sense for some event types, e.g. setting the value for EV_REL is pointless.

This is a local modification only affecting only this representation of this device. A future call to libevdev_get_event_value() will return this value, unless the value was overwritten by an event.

If the device supports ABS_MT_SLOT, the value set for any ABS_MT_* event code is the value of the currently active slot. You should use libevdev_set_slot_value() instead.

If the device supports ABS_MT_SLOT and the type is EV_ABS and the code is ABS_MT_SLOT, the value must be a positive number less then the number of slots on the device. Otherwise, libevdev_set_event_value() returns -1.

Parameters
devThe evdev device, already initialized with libevdev_set_fd()
typeThe event type for the code to query (EV_SYN, EV_REL, etc.)
codeThe event code to set the value for, one of ABS_X, LED_NUML, etc.
valueThe new value to set
Returns
0 on success, or -1 on failure.
Return values
-1the device does not have the event type or code enabled, or the code is outside the allowed limits for the given type, or the type cannot be set, or the value is not permitted for the given code.
See also
libevdev_set_slot_value
libevdev_get_event_value
void libevdev_set_id_bustype ( struct libevdev *  dev,
int  bustype 
)
Parameters
devThe evdev device
bustypeThe bustype to assign to this device
Note
This function may be called before libevdev_set_fd(). A call to libevdev_set_fd() will overwrite any previously set value.
void libevdev_set_id_product ( struct libevdev *  dev,
int  product_id 
)
Parameters
devThe evdev device
product_idThe product ID to assign to this device
Note
This function may be called before libevdev_set_fd(). A call to libevdev_set_fd() will overwrite any previously set value.
void libevdev_set_id_vendor ( struct libevdev *  dev,
int  vendor_id 
)
Parameters
devThe evdev device
vendor_idThe vendor ID to assign to this device
Note
This function may be called before libevdev_set_fd(). A call to libevdev_set_fd() will overwrite any previously set value.
void libevdev_set_id_version ( struct libevdev *  dev,
int  version 
)
Parameters
devThe evdev device
versionThe version to assign to this device
Note
This function may be called before libevdev_set_fd(). A call to libevdev_set_fd() will overwrite any previously set value.
void libevdev_set_name ( struct libevdev *  dev,
const char *  name 
)

Change the device's name as returned by libevdev_get_name().

This function destroys the string previously returned by libevdev_get_name(), a caller must take care that no references are kept.

Parameters
devThe evdev device
nameThe new, non-NULL, name to assign to this device.
Note
This function may be called before libevdev_set_fd(). A call to libevdev_set_fd() will overwrite any previously set value.
void libevdev_set_phys ( struct libevdev *  dev,
const char *  phys 
)

Change the device's physical location as returned by libevdev_get_phys().

This function destroys the string previously returned by libevdev_get_phys(), a caller must take care that no references are kept.

Parameters
devThe evdev device
physThe new phys to assign to this device.
Note
This function may be called before libevdev_set_fd(). A call to libevdev_set_fd() will overwrite any previously set value.
int libevdev_set_slot_value ( struct libevdev *  dev,
unsigned int  slot,
unsigned int  code,
int  value 
)

Set the value for a given code for the given slot.

This is a local modification only affecting only this representation of this device. A future call to libevdev_get_slot_value() will return this value, unless the value was overwritten by an event.

This function does not set event values for axes outside the ABS_MT range, use libevdev_set_event_value() instead.

Parameters
devThe evdev device, already initialized with libevdev_set_fd()
slotThe numerical slot number, must be smaller than the total number of slots on this device
codeThe event code to set the value for, one of ABS_MT_POSITION_X, etc.
valueThe new value to set
Returns
0 on success, or -1 on failure.
Return values
-1the device does not have the event code enabled, or the code is outside the allowed limits for multitouch events, or the slot number is outside the limits for this device, or the device does not support multitouch events.
See also
libevdev_set_event_value
libevdev_get_slot_value
void libevdev_set_uniq ( struct libevdev *  dev,
const char *  uniq 
)

Change the device's unique identifier as returned by libevdev_get_uniq().

This function destroys the string previously returned by libevdev_get_uniq(), a caller must take care that no references are kept.

Parameters
devThe evdev device
uniqThe new uniq to assign to this device.
Note
This function may be called before libevdev_set_fd(). A call to libevdev_set_fd() will overwrite any previously set value.