Introduction to libxcb

The libxcb package provides an interface to the X Window System protocol, which replaces the current Xlib interface. Xlib can also use XCB as a transport layer, allowing software to make requests and receive responses with both.

Package Information

Additional Downloads

libxcb Dependencies


libXau-1.0.3, libXdmcp-1.0.2, libpthread-stubs-0.1, xcb-proto-1.0, and libxslt-1.1.22


Doxygen-1.5.2 (to generate API documentation) and Check (to run tests)

User Notes:

Installation of libxcb

Install libxcb by running the following commands:

patch -Np1 -i ../libxcb-1.0-sloppy_lock-1.patch &&
./configure $XORG_CONFIG --docdir='${datadir}'/doc/libxcb-1.0 &&

To test the results, issue: make check.

Now, as the root user:

make install

Command Explanations

--docdir='${datadir}'/doc/libxcb-1.0: This parameter ensures the libxcb documentation is installed to a versioned directory.

--without-doxygen: This switch can be used to disable the API documentation if Doxygen-1.5.2 is installed.

Configuring libxcb

Configuration Information

The libxcb developers have decided to be strict in asserting locking bugs in X11 applications. This is different than the behavior of libX11 when used on its own, and it will cause some applications to crash when they previously did not. When an application has these types of bugs, it will crash with the following assertion:

xcb_xlib_lock: Assertion `!c->xlib.lock' failed.

The patch applied above to libxcb adds an environment variable, LIBXCB_ALLOW_SLOPPY_LOCK, to be set which will allow the locking bugs to not crash the application. It is a workaround that is known to be needed in a few cases. If it is found that these bugs affect an application in use, add the following to your system or personal profile:



Installed Programs: None
Installed Libraries: libxcb.{so,a} and libxcb-*.{so,a}
Installed Directories: $XORG_PREFIX/include/xcb and $XORG_PREFIX/share/doc/libxcb-1.0

Short Descriptions


is an interface to the X Window System protocol.

Last updated on 2008-08-11 10:11:37 -0500