[Bf-committers] Re: attempt to fix opengl query crashes under linux committed

[erwin at erwincoumans.com]

Are you sure?
Do you have some call stack? 

Thanks,
Erwin 


Austin Benesh writes: 

> I tried it and I don't believe that it's been fixed. Sorry. 
> 
> - Austin 
> 
> erwin at erwincoumans.com wrote:
>> 
>> We fixed number 1 and 2 from the list below. Do we actually link with 
>> pthreads under linux?
>> Can someone confirm things improved with latest CVS build?
>> Thanks,
>> Erwin 
>> 
>>  
>> 
>> 
>> from http://dri.sourceforge.net/doc/DRIuserguide.html
>> "
>> 11.5 libGL.so and dlopen()
>> 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.
>> 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:
>> 1  * 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, nested opening of dynamic libraries does not work.
>> 2  * 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.
>> 3  * 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.
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