xcb_xkb_get_device_info(3)

💖 xcb_xkb_get_device_info(3) — the XCB Requests glow-up 💖

okay bestie, gather round, because today we're meeting xcb_xkb_get_device_info, one of the XCB request girlies from the XKB chapter of libxcb. it lives in section 3 of the manual (the library-function section, iykyk), and it's giving "ask the X server about a keyboard device" main character energy. let's get into it 🎀

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✨ SYNOPSIS ✨

first thing you do, always: pull in the header. she's not optional.

#include <xcb/xkb.h>

🦋 Request function

here's the actual call, hand it your connection and a whole lil lineup of args:

xcb_xkb_get_device_info_cookie_t
xcb_xkb_get_device_info(xcb_connection_t *conn,
                        xcb_xkb_device_spec_t deviceSpec, uint16_t wanted,
                        uint8_t allButtons, uint8_t firstButton, uint8_t nButtons,
                        xcb_xkb_led_class_spec_t ledClass, xcb_xkb_id_spec_t ledID);

🌸 Reply datastructure

this is the struct you get back, field for field, no edits, no notes:

typedef struct xcb_xkb_get_device_info_reply_t {
    uint8_t    response_type;
    uint8_t    deviceID;
    uint16_t   sequence;
    uint32_t   length;
    uint16_t   present;
    uint16_t   supported;
    uint16_t   unsupported;
    uint16_t   nDeviceLedFBs;
    uint8_t    firstBtnWanted;
    uint8_t    nBtnsWanted;
    uint8_t    firstBtnRtrn;
    uint8_t    nBtnsRtrn;
    uint8_t    totalBtns;
    uint8_t    hasOwnState;
    uint16_t   dfltKbdFB;
    uint16_t   dfltLedFB;
    uint8_t    pad0[2];
    xcb_atom_t devType;
    uint16_t   nameLen;
} xcb_xkb_get_device_info_reply_t;

💅 Reply function

this is how you actually collect the reply for that cookie. errors? you handle them here, through e:

xcb_xkb_get_device_info_reply_t
*xcb_xkb_get_device_info_reply(xcb_connection_t *conn,
                               xcb_xkb_get_device_info_cookie_t cookie,
                               xcb_generic_error_t **e);

🧚 Reply accessors

the little helper squad that digs into the reply for you. copying these exactly, character for character, because that's the law:

xcb_xkb_string8_t *xcb_xkb_get_device_info_name(const
       xcb_xkb_get_device_info_request_t *reply);

int xcb_xkb_get_device_info_name_length(const
       xcb_xkb_get_device_info_reply_t *reply);

xcb_generic_iterator_t xcb_xkb_get_device_info_name_end(const
       xcb_xkb_get_device_info_reply_t *reply); uint8_t
       *xcb_xkb_get_device_info_pad_1 (const
       xcb_xkb_get_device_info_request_t *reply)

xcb_xkb_action_t *xcb_xkb_get_device_info_btn_actions(const
       xcb_xkb_get_device_info_request_t *reply);

int xcb_xkb_get_device_info_btn_actions_length(const
       xcb_xkb_get_device_info_reply_t *reply);

xcb_xkb_action_iterator_t
       xcb_xkb_get_device_info_btn_actions_iterator(const
       xcb_xkb_get_device_info_reply_t *reply);

int xcb_xkb_get_device_info_leds_length(const
       xcb_xkb_get_device_info_reply_t *reply);

xcb_xkb_device_led_info_iterator_t
       xcb_xkb_get_device_info_leds_iterator(const
       xcb_xkb_get_device_info_reply_t *reply);

not me noticing name_end and pad_1 are just chilling on the same line in the source. iconic formatting, no notes. 💀

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🫶 REQUEST ARGUMENTS

everything you gotta feed the request function:

• conn — the XCB connection to X11. your link to the server, bestie, without her you're just yelling into the void.
• deviceSpec — TODO: NOT YET DOCUMENTED. yeah, the docs girlies left this one blank 🙈
• wanted — TODO: NOT YET DOCUMENTED.
• allButtons — TODO: NOT YET DOCUMENTED.
• firstButton — TODO: NOT YET DOCUMENTED.
• nButtons — TODO: NOT YET DOCUMENTED.
• ledClass — TODO: NOT YET DOCUMENTED.
• ledID — TODO: NOT YET DOCUMENTED.

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💜 REPLY FIELDS

what every field in that reply struct actually means (or doesn't, in some cases, and I'm being so fr about that):

• response_type — the type of this reply, in this case XCB_XKB_GET_DEVICE_INFO. this field is also present in the xcb_generic_reply_t and can be used to tell replies apart from each other. she's the name tag at the party ✨
• sequence — the sequence number of the last request processed by the X11 server.
• length — the length of the reply, in words (a word is 4 bytes). yes, 4 bytes, don't come for me.
• deviceID — TODO: NOT YET DOCUMENTED.
• present — TODO: NOT YET DOCUMENTED.
• supported — TODO: NOT YET DOCUMENTED.
• unsupported — TODO: NOT YET DOCUMENTED.
• nDeviceLedFBs — TODO: NOT YET DOCUMENTED.
• firstBtnWanted — TODO: NOT YET DOCUMENTED.
• nBtnsWanted — TODO: NOT YET DOCUMENTED.
• firstBtnRtrn — TODO: NOT YET DOCUMENTED.
• nBtnsRtrn — TODO: NOT YET DOCUMENTED.
• totalBtns — TODO: NOT YET DOCUMENTED.
• hasOwnState — TODO: NOT YET DOCUMENTED.
• dfltKbdFB — TODO: NOT YET DOCUMENTED.
• dfltLedFB — TODO: NOT YET DOCUMENTED.
• devType — TODO: NOT YET DOCUMENTED.
• nameLen — TODO: NOT YET DOCUMENTED.

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🌈 DESCRIPTION

okay so... this section is genuinely empty in the source. nothing. blank. the void stared back. not me being handed an empty <section> and told to make it cute 😭 moving on, periodt.

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⭐ RETURN VALUE

• she hands you back an xcb_xkb_get_device_info_cookie_t. that's the vibe.
• errors have to be handled when calling the reply function xcb_xkb_get_device_info_reply.
• if you'd rather handle errors in the event loop instead, use xcb_xkb_get_device_info_unchecked. see xcb-requests(3) for details. iykyk.

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👑 ERRORS

this request does never generate any errors. like, none. zero. a clean girl. slay 💅

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🔥 SEE ALSO

this section is empty in the source too. no cross-references, no friends, just vibes 🦋

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💖 AUTHOR

generated from xkb.xml. contact xcb@lists.freedesktop.org for corrections and improvements.

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okay bestie, that's the whole page, every last field and TODO preserved with love 🫶 this page shipped as part of X Version 11 / libxcb 1.17.0, and yes, that's the source and version tag you'd find in the footer of the original — consider this your cute sign-off. go forth and get that device info, you absolute icon 🎀✨💜