xcb_shm_create_segment(3)

💖 NAME 💖

xcb_shm_create_segment — bestie, this one literally asks the server to allocate a shared memory segment for you 🫶

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✨ SYNOPSIS ✨

#include <xcb/shm.h>

🎀 Request function

xcb_shm_create_segment_cookie_t
       xcb_shm_create_segment(xcb_connection_t *conn,
       xcb_shm_seg_t shmseg, uint32_t size, uint8_t read_only);

🦋 Reply datastructure

typedef struct xcb_shm_create_segment_reply_t {
    uint8_t  response_type;
    uint8_t  nfd;
    uint16_t sequence;
    uint32_t length;
    uint8_t  pad0[24];
} xcb_shm_create_segment_reply_t;

🌸 Reply function

xcb_shm_create_segment_reply_t
       *xcb_shm_create_segment_reply(xcb_connection_t *conn,
       xcb_shm_create_segment_cookie_t cookie, xcb_generic_error_t **e);

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💅 REQUEST ARGUMENTS 💅

• conn — the XCB connection to X11, obvs. your lil hotline to the server 📞
• shmseg — a shared memory segment ID that you made with xcb_generate_id(). gotta generate it first, no skipping steps bestie ✨
• size — how big the segment you're creating should be. the size, the moment, the everything 💖
• read_only — True if the server should map the segment read-only; otherwise false. so like... can the server touch it or just look respectfully 👀

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👑 REPLY FIELDS 👑

• response_type — the type of this reply, which in this case is XCB_SHM_CREATE_SEGMENT. this field also lives in the xcb_generic_reply_t and it's how you tell your replies apart from each other, iykyk 🏷️
• sequence — the sequence number of the last request the X11 server processed 🔢
• length — the length of the reply, in words. and a word is 4 bytes, periodt 📏
• nfd — the number of file descriptors sent by the server. it will always be 1. no cap, always one 🤝
• shm_fd — TODO: NOT YET DOCUMENTED. the docs simply have not caught up yet, we love an unfinished icon 💀

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🌈 DESCRIPTION 🌈

It asks the server to allocate a shared memory segment. and the server's reply? it will include a file descriptor for the client to pass to mmap(). that's the whole point, that's the moment, that's the vibe 🧚

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🔥 RETURN VALUE 🔥

It returns an xcb_shm_create_segment_cookie_t. errors have to be handled when you call the reply function xcb_shm_create_segment_reply. so don't just ghost the cookie, bestie 😭

If you'd rather handle errors in the event loop instead, use xcb_shm_create_segment_unchecked. see xcb-requests(3) for the details on that whole situation.

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💀 ERRORS 💀

This request does never generate any errors. zero. none. she's chill like that 🙈

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🫶 SEE ALSO 🫶

• xcb-requests(3)

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💜 AUTHOR 💜

Generated from shm.xml. Contact xcb@lists.freedesktop.org for corrections and improvements. they're literally asking for your feedback, so slay ✨

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okay that's the whole page, you ate that 💅 this was xcb_shm_create_segment(3), part of libxcb 1.17.0 from X Version 11 — mwah, go mmap something iconic 💖✨🎀