Resolving symbols for dynamically loaded GL libs

[zackr]

There's a wonky case of applications which don't link to GL, linking to a library which doesn't link to GL but dlopens another library which links to GL. In this case our dlsym seems to return NULL for gl/glx symbols and the glxtrace.so exits with:
error: unavailable function "glXGetProcAddressARB"
testing:
starting any Qt 4.7+ application with argument "-graphicssystem opengl" e.g.:
qapitrace -graphicsssytem opengl
assistant -graphicssystem opengl
and so on (qtopengl library needs to be installed).

[jrfonseca]

This problem illustrates yet another limitation of LD_PRELOAD.

The QT apps dlopen libqglgraphicssystem.so , which is dynamically linked to libGL.so (it does not dlopen("libGL.so") directly), so when glxtrace.so tries to find the real libGL symbols with dlsym(RTLD_NEXT) it fails.

Seems a tricky one too...

[jrfonseca]

This problem illustrates yet another limitation of LD_PRELOAD.

The QT apps dlopen libqglgraphicssystem.so , which is dynamically linked to libGL.so (it does not dlopen("libGL.so") directly), so when glxtrace.so tries to find the real libGL symbols with dlsym(RTLD_NEXT) it fails.

Seems a tricky one too...

[jrfonseca]

Should be fixed now.

[akasilov]

Hi I am trying to debug trace OpenGL ES API of Qt 5.5 Application and I have the same issue with error: unavailable function "glXGetProcAddressARB".
My system is Ubuntu 14.04 running on VMWare. Should this problem be fixed or is it something different?
Thank you!