---
name: "XkbAllocDeviceInfo"
section: "3"
platform: "linux"
package: "libx11"
version: "1.8.14-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/XkbAllocDeviceInfo"
---

# XkbAllocDeviceInfo(3)

Obtain an XkbDeviceInfoRec structure

## NAME

XkbAllocDeviceInfo - Obtain an XkbDeviceInfoRec structure

## SYNOPSIS

**XkbDeviceInfoPtr XkbAllocDeviceInfo** **(unsigned int** *device\_spec***,** **unsigned int** *n\_buttons***,** **unsigned int** *sz\_leds***);**

## ARGUMENTS

- *device\_spec*

  device ID with which structure will be used

- *n\_buttons*

  number of button actions to allocate space for

- *sz\_leds*

  number of LED feedbacks to allocate space for

## DESCRIPTION

*XkbAllocDeviceInfo* allocates space for an XkbDeviceInfoRec structure and initializes that structure's *device\_spec* field with the device ID specified by *device\_spec.* If *n\_buttons* is nonzero, *n\_buttons* XkbActions are linked into the XkbDeviceInfoRec structure and initialized to zero. If *sz\_leds* is nonzero, *sz\_leds* XkbDeviceLedInfoRec structures are also allocated and linked into the XkbDeviceInfoRec structure. If you request XkbDeviceLedInfoRec structures be allocated using this request, you must initialize them explicitly, by using [**XkbAddDeviceLedInfo**(3)](/XkbAddDeviceLedInfo/3.md).

## STRUCTURES

Information about X Input Extension devices is transferred between a client program and the Xkb extension in an XkbDeviceInfoRec structure:

```
    typedef struct {
        char *               name;          /* name for device */
        Atom                 type;          /* name for class of devices */
        unsigned short       device_spec;   /* device of interest */
        Bool                 has_own_state; /* True=>this device has its own state */
        unsigned short       supported;     /* bits indicating supported capabilities */
        unsigned short       unsupported;   /* bits indicating unsupported capabilities */
        unsigned short       num_btns;      /* number of entries in btn_acts */
        XkbAction *          btn_acts;      /* button actions */
        unsigned short       sz_leds;       /* total number of entries in LEDs vector */
        unsigned short       num_leds;      /* number of valid entries in LEDs vector */
        unsigned short       dflt_kbd_fb;   /* input extension ID of default (core kbd) indicator */
        unsigned short       dflt_led_fb;   /* input extension ID of default indicator feedback */
        XkbDeviceLedInfoPtr  leds;          /* LED descriptions */
    } XkbDeviceInfoRec, *XkbDeviceInfoPtr;
    typedef struct {
        unsigned short      led_class;        /* class for this LED device*/
        unsigned short      led_id;           /* ID for this LED device */
        unsigned int        phys_indicators;  /* bits for which LEDs physically present */
        unsigned int        maps_present;     /* bits for which LEDs have maps in maps */
        unsigned int        names_present;    /* bits for which LEDs are in names */
        unsigned int        state;            /* 1 bit => corresponding LED is on */
        Atom                names[XkbNumIndicators];   /* names for LEDs */
        XkbIndicatorMapRec  maps;             /* indicator maps for each LED */
    } XkbDeviceLedInfoRec, *XkbDeviceLedInfoPtr;
```

## SEE ALSO

[**XkbAddDeviceLedInfo**(3)](/XkbAddDeviceLedInfo/3.md)