With the advent of the Present extension, some events (such as
PresentCompleteNotify) now use native 64-bit types on the wire.
For XGE events, we insert an extra "uint32_t full_sequence" field
immediately after the first 32 bytes of data. Normally, this causes
the subsequent fields to be shifted over by 4 bytes, and the structure
to grow in size by 4 bytes. Everything works fine.
However, if event contains 64-bit extended fields, this may result in
the compiler adding an extra 4 bytes of padding so that those fields
remain aligned on 64-bit boundaries. This causes the structure to grow
by 8 bytes, not 4. Unfortunately, XCB doesn't realize this, and
always believes that the length only increased by 4. read_packet()
then fails to malloc enough memory to hold the event, and the event
processing code uses the wrong offsets.
To fix this, mark any event structures containing 64-bit extended
fields with __attribute__((__packed__)).
v2: Use any(...) instead of True in (...), as suggested by
Daniel Martin.
v3 (Alan Coopersmith): Fix build with Solaris Studio 12.3 by moving the
attribute to after the structure definition.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Keith Packard <keithp@keithp.com> [v1]
Reviewed-by: Josh Triplett <josh@joshtriplett.org> [v1]
Reviewed-by: Daniel Martin <consume.noise@gmail.com>
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
|
||
|---|---|---|
| doc | ||
| m4 | ||
| src | ||
| tests | ||
| tools | ||
| .autom4te.cfg | ||
| .gitignore | ||
| COPYING | ||
| INSTALL | ||
| Makefile.am | ||
| NEWS | ||
| README | ||
| autogen.sh | ||
| configure.ac | ||
| xcb-composite.pc.in | ||
| xcb-damage.pc.in | ||
| xcb-dpms.pc.in | ||
| xcb-dri2.pc.in | ||
| xcb-dri3.pc.in | ||
| xcb-glx.pc.in | ||
| xcb-present.pc.in | ||
| xcb-randr.pc.in | ||
| xcb-record.pc.in | ||
| xcb-render.pc.in | ||
| xcb-res.pc.in | ||
| xcb-screensaver.pc.in | ||
| xcb-shape.pc.in | ||
| xcb-shm.pc.in | ||
| xcb-sync.pc.in | ||
| xcb-xevie.pc.in | ||
| xcb-xf86dri.pc.in | ||
| xcb-xfixes.pc.in | ||
| xcb-xinerama.pc.in | ||
| xcb-xinput.pc.in | ||
| xcb-xkb.pc.in | ||
| xcb-xprint.pc.in | ||
| xcb-xselinux.pc.in | ||
| xcb-xtest.pc.in | ||
| xcb-xv.pc.in | ||
| xcb-xvmc.pc.in | ||
| xcb.pc.in | ||
About libxcb
============
libxcb provides an interface to the X Window System protocol, which
replaces the current Xlib interface. It has several advantages over
Xlib, including:
- size: small, simple library, and lower memory footprint
- latency hiding: batch several requests and wait for the replies later
- direct protocol access: interface and protocol correspond exactly
- proven thread support: transparently access XCB from multiple threads
- easy extension implementation: interfaces auto-generated from XML-XCB
Xlib can also use XCB as a transport layer, allowing software to make
requests and receive responses with both, which eases porting to XCB.
However, client programs, libraries, and toolkits will gain the most
benefit from a native XCB port.
Please report any issues you find to the freedesktop.org bug tracker,
at:
<https://bugs.freedesktop.org/enter_bug.cgi?product=XCB>
Discussion about XCB occurs on the XCB mailing list:
<mailto:xcb at lists.freedesktop.org>
<http://lists.freedesktop.org/mailman/listinfo/xcb>
You can obtain the latest development versions of XCB using GIT.
For anonymous checkouts, use:
git clone git://anongit.freedesktop.org/git/xcb/libxcb
For developers, use:
git clone git+ssh://git.freedesktop.org/git/xcb/libxcb