if (rootstream_capture_init(ctx) < 0) {
    fprintf(stderr, "ERROR: Capture init failed\n");
    return -1;  // HARD FAIL - application exits
}

/*
 * x11_capture.c - X11 SHM screen capture fallback
 * 
 * Uses XGetImage or XShmGetImage to grab screen.
 * Falls back to XGetImage if XShm unavailable.
 * No compositor dependency - works on X11 directly.
 */

#include "../include/rootstream.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#ifdef HAVE_X11
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#ifdef HAVE_X11_SHM
#include <X11/extensions/XShm.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#endif
#endif

typedef struct {
    Display *display;
    Window root;
    int width;
    int height;
    int depth;
    XImage *image;
#ifdef HAVE_X11_SHM
    XShmSegmentInfo shminfo;
    bool use_shm;
#endif
} x11_capture_ctx_t;

static void set_error(const char *msg) {
    /* Store error for rootstream_get_error() */
}

/*
 * Initialize X11 capture
 */
int rootstream_capture_init_x11(rootstream_ctx_t *ctx) {
#ifndef HAVE_X11
    set_error("X11 support not compiled in");
    return -1;
#else
    x11_capture_ctx_t *x11 = calloc(1, sizeof(x11_capture_ctx_t));
    if (!x11) {
        set_error("Memory allocation failed");
        return -1;
    }

    /* Open X display */
    x11->display = XOpenDisplay(NULL);
    if (!x11->display) {
        set_error("Cannot open X11 display");
        free(x11);
        return -1;
    }

    /* Get root window */
    int screen = DefaultScreen(x11->display);
    x11->root = RootWindow(x11->display, screen);
    
    /* Get window attributes */
    XWindowAttributes attrs;
    if (!XGetWindowAttributes(x11->display, x11->root, &attrs)) {
        set_error("Cannot get root window attributes");
        XCloseDisplay(x11->display);
        free(x11);
        return -1;
    }

    x11->width = attrs.width;
    x11->height = attrs.height;
    x11->depth = attrs.depth;

    /* Try XShm */
#ifdef HAVE_X11_SHM
    if (XShmQueryExtension(x11->display)) {
        x11->image = XShmCreateImage(x11->display, attrs.visual,
                                     x11->depth, ZPixmap, NULL,
                                     &x11->shminfo, x11->width, x11->height);
        if (x11->image) {
            x11->shminfo.shmid = shmget(IPC_PRIVATE,
                                       x11->image->bytes_per_line * x11->height,
                                       IPC_CREAT | 0777);
            if (x11->shminfo.shmid >= 0) {
                x11->shminfo.shmaddr = x11->image->data = 
                    (char *)shmat(x11->shminfo.shmid, 0, 0);
                
                if (x11->shminfo.shmaddr != (char *)-1) {
                    x11->shminfo.readOnly = False;
                    if (XShmAttach(x11->display, &x11->shminfo)) {
                        x11->use_shm = true;
                        printf("✓ X11 capture using XShm\n");
                    }
                }
            }
        }
    }
#endif

    /* Fallback to regular XGetImage if XShm unavailable/failed */
    if (!x11->image) {
#ifdef HAVE_X11_SHM
        x11->use_shm = false;
#endif
        x11->image = XGetImage(x11->display, x11->root, 0, 0,
                              x11->width, x11->height, AllPlanes, ZPixmap);
        if (!x11->image) {
            set_error("XGetImage failed");
            XCloseDisplay(x11->display);
            free(x11);
            return -1;
        }
        printf("✓ X11 capture using XGetImage\n");
    }

    /* Allocate frame buffer */
    size_t frame_size = x11->width * x11->height * 4;  /* RGBA */
    ctx->current_frame.data = malloc(frame_size);
    if (!ctx->current_frame.data) {
        set_error("Frame buffer allocation failed"...

</details>



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