diff options
Diffstat (limited to 'xc')
| -rw-r--r-- | xc/programs/Xserver/hw/xfree86/doc/sgml/DRI.sgml | 46 |
1 files changed, 45 insertions, 1 deletions
diff --git a/xc/programs/Xserver/hw/xfree86/doc/sgml/DRI.sgml b/xc/programs/Xserver/hw/xfree86/doc/sgml/DRI.sgml index 795c01c62..a4dd1f4f6 100644 --- a/xc/programs/Xserver/hw/xfree86/doc/sgml/DRI.sgml +++ b/xc/programs/Xserver/hw/xfree86/doc/sgml/DRI.sgml @@ -10,7 +10,7 @@ <title>DRI User Guide <author><htmlurl url="http://www.precisioninsight.com/" name="Precision Insight, Inc."> - <date>5 April 2000 + <date>15 April 2000 <ident> $XFree86: xc/programs/Xserver/hw/xfree86/doc/sgml/DRI.sgml,v 1.3 2000/04/05 05:38:41 brianp Exp $ @@ -747,6 +747,50 @@ which will be addressed in the future. + <sect1>libGL.so and dlopen() +<p> + A number of popular OpenGL applications on Linux (such as Quake3, + HereticII, Heavy Gear 2, etc) dynamically open the libGL.so + library at runtime with dlopen(), rather than linking with -lGL + at compile/link time. +<p> + If dynamic loading of libGL.so is not implemented carefully, there + can be a number of serious problems. + Here are the things to be careful of in your application: + <itemize> + <item>Specify the RTLD_GLOBAL flag to dlopen(). + If you don't do this then you'll likely see a runtime error message + complaining that _glapi_Context is undefined when libGL.so + tries to open a hardware-specific driver. + Without this flag, <em>nested</em> opening of dynamic libraries + does not work. + <item>Do not close the library with dlclose() until after + XCloseDisplay() has been called. + When libGL.so initializes itself it registers several callbacks + functions with Xlib. + When XCloseDisplay() is called those callback functions are + called. + If libGL.so has already been unloaded with dlclose() this will + cause a segmentation fault. + <item> + Your application should link with -lpthread. + On Linux, libGL.so uses the pthreads library in order to provide + thread safety. + There is apparently a bug in the dlopen()/dlclose() code which + causes crashes if the library uses pthreads but the parent + application doesn't. + The only known work-around is to link the application with + -lpthread. + </itemize> + + Some applications don't yet incorporate these procedures and + may fail. + For example, changing the graphics settings in some video games + will expose this problem. + The DRI developers are working with game vendors to prevent this + problem in the future. + + <sect1>Bug Database <p> The DRI bug database which includes bugs related to specific |