I downloaded the latest Blender 4.4.0 binary, but it frequently fails to start on RHEL9 with the following error. How can I resolve this issue? The issue happens in an X11 session that is started from an xfce desktop session. Moreover, the issue sometimes happens but sometimes doesn't. $ ./blender-4.4.0-linux-x64/blender -d Switching to fully guarded memory allocator. Blender 4.4.0 Build: 2025-03-18 03:01:40 Linux Release argv = ./blender-4.4.0-linux-x64/blender argv[1] = -d GHOST/Wayland: error: XDG_RUNTIME_DIR is invalid or not set in the environment. ./blender-4.4.0-linux-x64/blender() [0x104e610] /lib64/libwayland-client.so.0(+0x6c8a) [0x7f590a01ac8a] /lib64/libwayland-client.so.0(wl_display_connect+0x310) [0x7f590a01f7b0] ./blender-4.4.0-linux-x64/blender() [0x1616494] ./blender-4.4.0-linux-x64/blender() [0x15fb3b4] ./blender-4.4.0-linux-x64/blender() [0x15f9730] ./blender-4.4.0-linux-x64/blender() [0x12c67b4] ./blender-4.4.0-linux-x64/blender() [0x12a5f55] ./blender-4.4.0-linux-x64/blender() [0x74a573] /lib64/libc.so.6(+0x3feb0) [0x7f5d26798eb0] /lib64/libc.so.6(__libc_start_main+0x80) [0x7f5d26798f60] ./blender-4.4.0-linux-x64/blender() [0x88d0ee] [xcb] Unknown sequence number while processing queue [xcb] Most likely this is a multi-threaded client and XInitThreads has not been called [xcb] Aborting, sorry about that. blender: xcb_io.c:269: poll_for_event: Assertion `!xcb_xlib_threads_sequence_lost' failed. Aborted (core dumped)

I'm trying to use a Qt6-based program, namely NVIDIA's Nsight Compute UI , on a machine running SLES 15 SP5 (SUSE Enterprise Linux 2015, service pack 5). No, I can't switch distributions, it's not my decision :-( Anyway, the program used to run fine in all its versions from 2023, but with more recent versions, I get:

- Error: libxcb-cursor.so.0: cannot open shared object file: No such file or directory

(for the long version, see below). Now, I can install packages on this machine, but - there is no libxcb-cursor package; there are a bunch of other libxcb-whatevers, but not that particular one. So, how can I satisfy the library requirement for my application? ----------- Long version of the error message:

qt.qpa.plugin: From 6.5.0, xcb-cursor0 or libxcb-cursor0 is needed to load the Qt xcb platform plugin.
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: xcb, wayland, offscreen, wayland-egl.

Application could not be initialized!
    This is likely due to missing Qt platform dependencies.
    For a list of dependencies, please refer to https://doc.qt.io/qt-6/linux-requirements.html 
    To view missing libraries, set QT_DEBUG_PLUGINS=1 and re-run the application.

Warning: OpenGL Version check failed. Falling back to Mesa software rendering.
qt.qpa.plugin: From 6.5.0, xcb-cursor0 or libxcb-cursor0 is needed to load the Qt xcb platform plugin.
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: xcb, wayland, offscreen, wayland-egl.

################# ERROR: CrashReporter #################
CrashReporter

Qt initialization failed

Failed to load Qt platform plugin: "xcb"
 - Library path: /opt/versions/nvidia/nsight-compute/2024.3/host/linux-desktop-glibc_2_11_3-x64/Plugins/platforms/libqxcb.so
 - Error: libxcb-cursor.so.0: cannot open shared object file: No such file or directory

Please check if libxcb-cursor.so.0 has been installed on your system
See https://doc.qt.io/qt-6/linux-requirements.html  for more details.
Application is going to abort
Warning: Missing charsets in String to FontSet conversion
/opt/versions/nvidia/nsight-compute/2024.3/host/linux-desktop-glibc_2_11_3-x64/ncu-ui: line 26: 26176 Aborted

Checking journalctl /usr/bin/sway I see lots of errors like this [xwayland/xwm.c:1286] xcb error: op 18:0, code 3, sequence 42593, value 4194450 What do they mean, is there any reason for concern there?

I'm 'make'-ing SXHKD on MX Linux to try keybindings and I get: $ make cc -std=c99 -pedantic -Wall -Wextra -D_POSIX_C_SOURCE=200112L -DVERSION=\"0.6.1\" -c -o sxhkd.o src/sxhkd.c src/sxhkd.c:25:10: fatal error: xcb/xcb_event.h: No such file or directory #include ^~~~~~~~~~~~~~~~~ compilation terminated. make: *** [: sxhkd.o] Error 1 Please help me understand, so if I'm not mistaken it's compiling sxhkd.c in the src folder, is the include header saying to go into an xcb folder and find xcb_event.h but the xcb folder is missing? I've looked everywhere on the net and I can't find xcb_event.h Honestly I'm not confident or experienced yet please lend me some direction. Thanks

I've programmed a key to run xdotool when it's pressed. But for some unknown reason xdotool is only sending keystrokes when the binded key is released, except when a non-active window is sent the keystrokes with --window, in which case it (as I would like it to do for the active window instead) sends the keystrokes as the binded key is pressed as well as repeatly when held down. Example code with the issue: #include #include #include int main() { xcb_connection_t *connection = xcb_connect(NULL, NULL); xcb_screen_t *screen = xcb_setup_roots_iterator(xcb_get_setup(connection)).data; xcb_grab_key(connection, 1, screen->root, XCB_NONE, 65, XCB_GRAB_MODE_ASYNC, XCB_GRAB_MODE_ASYNC); // 65=space (on mine at least) xcb_flush(connection); xcb_generic_event_t *event; while ( (event = xcb_wait_for_event(connection)) ) { switch (event->response_type & ~0x80) { case XCB_KEY_PRESS: { // UNCOMMENT ONE OF THE LINES BELOW // system("xdotool key q"); // only on release :( // system("xdotool getactivewindow key --window %1 q"); // only on release :( // system("xdotool key --window 18874376 q"); // (replace 18874376 with one of your window's id, could use 'xdotool getactivewindow') works perfectly for me but only if the specified window is not active :( break; } } free(event); } } Please note above doesn't work with modifiers on, including Num Lock. To compile it: gcc c.c -lxcb Do you experience the same and how do I get what I want?

I am trying to make an image appear under my cursor whenever I click on my desktop. I decided to use xcb to accomplish this. I figured I should capture the pointer from the root window (I don't really know a better way to do it), because I always want the image to appear, no matter where I click. The application that displays the image should not interfere with my normal workflow. Here is how I capture the pointer so far: #include #include #include #include #include #include #include #include #include #include void setup(xcb_connection_t *connection) { xcb_generic_error_t *err; xcb_screen_t *screen = xcb_setup_roots_iterator(xcb_get_setup(connection)).data; xcb_void_cookie_t grab_cookie = xcb_grab_button(connection, True, screen->root, XCB_NONE, XCB_GRAB_MODE_ASYNC, XCB_GRAB_MODE_ASYNC, XCB_NONE, XCB_NONE, XCB_BUTTON_INDEX_1, XCB_MOD_MASK_ANY); xcb_generic_error_t *error = xcb_request_check(connection, grab_cookie); if (error != NULL) { xcb_disconnect(connection); perror("could not subscribe to events on a window, bailing out"); exit(1); } free(error); xcb_flush(connection); } int main(int argc, char *argv[]) { xcb_generic_event_t *e; Display *dpy = XOpenDisplay(NULL); xcb_connection_t *connection = XGetXCBConnection(dpy); setup(connection); while ((e = xcb_wait_for_event(connection))) { switch(e->response_type & ~0x80) { case XCB_BUTTON_PRESS: printf("Click.\n"); break; default: break; } free(e); } xcb_ungrab_pointer(connection, XCB_TIME_CURRENT_TIME); } The code line that grabs the cursor is in the setup method: xcb_void_cookie_t grab_cookie = xcb_grab_button(connection, True, screen->root, XCB_NONE, XCB_GRAB_MODE_ASYNC, XCB_GRAB_MODE_ASYNC, XCB_NONE, XCB_NONE, XCB_BUTTON_INDEX_1, XCB_MOD_MASK_ANY); As far as I can tell by "autocorrecting" man xcb_grab_button, my pointer events should not be influenced if I put XCB_GRAB_MODE_ASYNC as the fifth argument to the function (the manual says something different, but it is generally quite poor, so I would be very surprised if it weren't by mistake). However, this is not the case: When I click, the click simply gets swallowed by my application and, e.g., Firefox does not react to it. How can grab the cursor such that my click events do not get eaten? If such a feature does not exist in X, would you recommend that I simply "resend" the click events or is there a better option? My window manager is i3, in case this information changes anything.

I'm trying to compile polybar, and I get a long compilation error which is related to xcb (apparently), I have the log file here ; I've read through the polybar wiki and I came upon the solution of downgrading xcb-proto to 1.11, and so I followed through with the process, although I'm not really sure how to check ther version (the logs tell me that each X-extension has version 1.13 though?) Nonetheless I've tried compiling with both Clang and GCC using build.sh, all to no avail, my question is how I can downgrade packages:

-- [X]   xcb-randr (1.13.1)
-- [X]   xcb-randr (monitor support) (1.13.1)
-- [X]   xcb-composite (1.13.1)
-- [X]   xcb-xkb (1.13.1)
[...]

to version 1.11? EDIT I have tried to remove the libxcb* packages from my Debian, and before I wrote yes on the prompt to continue I noticed it would make redundant a lot of packages that would otherwise be beneficial to my system, so I don't see how I can hotplug a downgrade without removing the packages I want to downgrade to begin with.

Currently, I have had no problems compiling and running applications using Xlib-xcb and GTK+. However I haven't found a way to integrate the two, to use together. For example, it's be nice to be able to copy an area from an xcb pixmap into a GDK or GTK+ pixmap or window any other GTK or GDK object. Or to receive x events mixed with GTK's events. Currently, I use a separate thread to run an event loop using xcb_wait_for_event() if I want to use GTK in the same application. Does GTK+ have any means of delivering regular x events? Currently, when I run a program mixing calls from Xlib-xcb and GTK+, I get two icons in the Ubuntu application launcher strip, which is ok, just annoying. I'm pretty sure this is because I must use a separate Display variable (for Xlib), and xcb_connection_t variable (for my xcb calls). The window manager must assume there're two applications, separately using X11. I'm just a hobbyist and I'm doing this for fun and to teach myself. So even if replies of "why would you want to do that," or "that's not a good idea" are sensible ones, I still want to do that and don't care if it's a bad idea. I'm having fun! There are kludges I've thought of which could allow me to get image data from one realm to the other, but I'm hoping to find out that GTK+ or GDK have a way for me to directly call Xlib-xcb and share the same connection, which I just haven't been able to find. Since it's all one client application, it makes sense to have only one connection to the X11 server right? And I can get events without any problem and as long as I don't grab the pointer, keyboard, etc., the GTK+ side works just fine. Yeah, it really does sound like a bad idea! and why WOULD I want to do this? I dunno. It's fun. BTW, Cairo can use a pixmap as a surface, or creates a surface that renders in the pixmap - I'm unsure the technical terms. I use Cairo for text instead of the X Windows text calls.