Re-hello, This man is getting guite happy with your XCB. I cannot run the programs from command line directly but all programs work very well when runned within the debugger (gdb). I have even seen a tiny blank, beautiful window made by the test2.c program. It's amazing. As said, the programs output rubbish and crash when runned directly from CLI (command line interface).   Actually, we've seen similar bugs in the Ubuntus X-window libraries before . Recent bug in the "XFig" program is one such an example. It worked well within the debugger but seg-faulted on CLI.   AFAIR it was s:thing with realloc() or free() on NULL pointers. DO NOT DESPAIR PEOPLE, i will hunt the bug ;-)  Alex has just learned to debug so... Cannot promise anything but here we go.... (This thread is closed so long) Sincerely   Alex. -------------------------------------------------------------------- This is what done so far: 1) Compile a sample code from the guide. $ gcc -Wall -g test2.c -o test2 `pkg-config --cflags --libs xcb` Run within debugger  ( gdb ./test2 ) $ LD_LIBRARY_PATH=/usr/local/lib  gdb ./test2 GNU gdb 6.3-debian Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB.  Type "show warranty" for details. This GDB was configured as "i486-linux-gnu"...Using host libthread_db library "/lib/tls/i686/cmov/libthread_db.so.1". (gdb) r Starting program: /home/alex/code/X11/test/test2 Informations of screen 117:   width.........: 1280   height........: 1024   white pixel...: 16777215   black pixel...: 0 ^C Program exited with code 01. (gdb) -------------------------- 2)  $ cd ../xcb-demo   ##  make clean && ./configure && make Compile w/ gcc-3.4 (Ubuntu 5.10 has gcc-4.x) $ make clean && CC=gcc-3.4 CFLAGS=-g  ./configure && make Run it $  LD_LIBRARY_PATH=/usr/local/lib gdb ./xcb-test GNU gdb 6.3-debian Copyright 2004 Free Software Foundation, Inc. <snip> <snip> (gdb) r Starting program: /home/alex/code/X11/xcb-demo/xcb-test [Thread debugging using libthread_db enabled] [New Thread -1209726752 (LWP 27661)] ALEX's OWN DEBUG: hostname= (NULL) ALEX's OWN DEBUG: socket name=/tmp/.X11-unix/X0   (fd=6) ALEX's OWN DEBUG: Connect fd = 6 Geometry for window 0x00000075: 1280x1024+0+0 Geometry for window 0x03800000: 150x150+5+23 Event ConfigureNotify following seqnum 6. Event ReparentNotify following seqnum 6. Event ConfigureNotify following seqnum 6. Event ConfigureNotify following seqnum 6 (from SendEvent). Event MapNotify following seqnum 6. Event Expose following seqnum 6. Window 0x03800000 has parent 0x00c75a00, root 0x00000075, and 0 children. Geometry for window 0x00c75a00: 160x178+15+118 Window 0x00c75a00 has parent 0x00000075, root 0x00000075, and 1 children:     window 0x03800000 Window 0x03800000 has attributes:     backingStore       = 2     visualID           = 0x23     class              = 1     bitGravity         = 0     winGravity         = 1     backingBitPlanes   = 0xffffffff     backingPixel       = 0     saveUnder          = 0     mapInstalled       = 1     mapState           = 2     override           = 0     colormap           = 0x00000020     allEventMasks      = 0x00e28038     yourEventMask      = 0x00028038     doNotPropagateMask = 0x00000004 Event EnterNotify following seqnum 12. Event LeaveNotify following seqnum 12. Event ConfigureNotify following seqnum 12 (from SendEvent). Event ConfigureNotify following seqnum 12 (from SendEvent). .... Sincerely    Alex Botero