[Xcb] [PATCH xcb/libxcb] Fatal error message when we close libX11 window application

[Alan Coopersmith]

That's libX11, not libxcb, and is simply an application error - since you
provided no handler for the window manager to send the request to close your
window gracefully, it killed your connection.  The program needs to handle
WM_DELETE_WINDOW messages if you want to avoid that - for an example, see
http://www.lemoda.net/c/xlib-wmclose/

	-Alan Coopersmith-              alan.coopersmith at oracle.com
	 Oracle Solaris Engineering - http://blogs.oracle.com/alanc

On 05/26/15 01:00 PM, robert somerville wrote:
> Hi Uri:
>
> here is the message when we hit the close button: ( I can send screen captures,
> if you wish  ( how ?) ) :
>
> XIO:  fatal IO error 11 (Resource temporarily unavailable) on X server
> "cgy530ws:0.0"
>        after 1304786 requests (1300490 known processed) with 0 events remaining.
>
>  > more tttt.cxx
>
> #include <X11/Xlib.h> // Every Xlib program must include this
> #include <assert.h>   // I include this to test return values the lazy way
> #include <unistd.h>   // So we got the profile for 10 seconds
> #include <stdio.h>
> #include <stdlib.h>
> #include <execinfo.h>
>
> #define NIL (0)       // A name for the void pointer
>
> void printBacktrace() {
>    int j, nptrs;
> #define SIZE 100
>    void *buffer[100];
>    char **strings;
>
>    nptrs = backtrace(buffer, SIZE);
>    printf("backtrace() returned %d addresses\n", nptrs);
>
>     /* The call backtrace_symbols_fd(buffer, nptrs, STDOUT_FILENO)
>         would produce similar output to the following: */
>
>    strings = backtrace_symbols(buffer, nptrs);
>    if (strings == NULL) {
>      perror("backtrace_symbols");
>      exit(EXIT_FAILURE);
>    }
>
>    for (j = 0; j < nptrs; j++)
>      printf("%s\n", strings[j]);
>
>    free(strings);
> }
>
> int myIOXError(Display *disp)
> {
>    printf("ERROR Received a X IO error on display=%x.\n", disp);
>    printBacktrace();
>    return True;
> }
>
> main() {
>    Display *dpy = XOpenDisplay(NIL);
>    assert(dpy);
>
>    int blackColor = BlackPixel(dpy, DefaultScreen(dpy));
>    int whiteColor = WhitePixel(dpy, DefaultScreen(dpy));
>
>    // Create the window
>    Window w = XCreateSimpleWindow(dpy, DefaultRootWindow(dpy), 0, 0,
>                                   200, 100, 0, blackColor, blackColor);
>
>    // We want to get MapNotify events
>    XSelectInput(dpy, w, StructureNotifyMask);
>
>    // "Map" the window (that is, make it appear on the screen)
>    XMapWindow(dpy, w);
>
>    // Create a "Graphics Context"
>    GC gc = XCreateGC(dpy, w, 0, NIL);
>
>    // Tell the GC we draw using the white color
>    XSetForeground(dpy, gc, whiteColor);
>
>    // register io error handler
> //  XSetIOErrorHandler(myIOXError);
>
>    // Wait for the MapNotify event
>    for(;;) {
>      XEvent e;
>      XNextEvent(dpy, &e);
>      if (e.type == MapNotify)
>        break;
>    }
>
>    // Draw the line
>    for(;;) {
>      XDrawLine(dpy, w, gc, 10, 60, 180, 20);
>      // Send the "DrawLine" request to the server
>      XFlush(dpy);
>    }
>
>    // Wait for 10 seconds
>    sleep(10);
> }
>
>
>
> ldd tttt
>          linux-vdso.so.1 =>  (0x00007f7786ae2000)
>          libX11.so.6 => /usr/lib64/libX11.so.6 (0x0000003ede200000)
>          libstdc++.so.6 => /usr/lib64/libstdc++.so.6 (0x0000003ee1e00000)
>          libm.so.6 => /lib64/libm.so.6 (0x0000003edb600000)
>          libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x0000003ee1600000)
>          libc.so.6 => /lib64/libc.so.6 (0x0000003edae00000)
>          libxcb.so.1 => /usr/lib64/libxcb.so.1 (0x0000003edda00000)
>          libdl.so.2 => /lib64/libdl.so.2 (0x0000003edba00000)
>          /lib64/ld-linux-x86-64.so.2 (0x0000003edaa00000)
>          libXau.so.6 => /usr/lib64/libXau.so.6 (0x0000003edde00000)
>
> On Tue, May 26, 2015 at 1:54 PM, Uli Schlachter <psychon at znc.in
> <mailto:psychon at znc.in>> wrote:
>
>     Hi,
>
>     Am 26.05.2015 um 12:02 schrieb robert somerville:
>      > Hello All:
>      > This is my first post to this group, please forgive any newbie mistakes ..
>      >
>      > We seem to be having this error on our Redhat 6.6 x86-64 system ! Is there
>      >  a version of XCB out there that will fix this problem ? This error occurs
>      > also in a third party API and is apparently killing us. It also occurs on a
>      > test drawing program when we close the window ( I believe we found it here,
>      > or nearby)
>      >
>      > Any suggestions how we should go about fixing this ???
>      > I believe (off the top of my head) that we are running Redhat libxcb-1.9.?
>
>     which error message? Which test drawing program? Any more information than
>     "there is an error message when we close our application"?
>
>     Cheers,
>     Uli
>     --
>     <alanc> I think someone had a Xprint version of glxgears at one point,
>          but benchmarking how many GL pages you can print per second
>          was deemed too silly to merge
>
>
>
>
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