On Tue, Mar 20, 2012 at 09:02:13AM +0000, Edd Barrett wrote:
> Hi,
>
> Having spoken to sthen and djm, I am still stuck on this, so I am posting on
> ports, incase someone here knows.
>
> Im looking at porting something which uses ctypes to load first libGL and then
> libGLU. Once we strip the gunk away, the library loading looks like this:
>
> ---8<---
> import ctypes
> ctypes.cdll.LoadLibrary("libGL.so")
> ctypes.cdll.LoadLibrary("libGLU.so")
> ---8<---
>
> Try it on a python shell. The final line spews errors about missing
> symbols:
>
> ---8<---
> python2.7:/usr/X11R6/lib/libGLU.so.7.0: undefined symbol 'glPixelStorei'
> python2.7:/usr/X11R6/lib/libGLU.so.7.0: undefined symbol 'glEvalPoint2'
> python2.7:/usr/X11R6/lib/libGLU.so.7.0: undefined symbol 'glMultMatrixd'
> python2.7:/usr/X11R6/lib/libGLU.so.7.0: undefined symbol 'glPopAttrib'
> ...
> ---8<---
>
> These symbols are from libGL.so (i used nm to check this), which we supposedly
> loaded on the previous line.
>
> I have used LD_DEBUG to check libGL is correctly loaded, and it is, log
> here:
> http://theunixzoo.co.uk/files/pylog
>
> I can even see the functions from the python interpreter:
> >>> libgl = ctypes.cdll.LoadLibrary("libGL.so")
> >>> libgl
> <CDLL 'libGL.so', handle 80270010 at 7c08f8ac>
> >>> libgl.glEnd
> <_FuncPtr object at 0x7c07402c>
>
> If you use LD_PRELOAD, all is well:
>
> ---8<---
> % LD_PRELOAD=/usr/X11R6/lib/libGLU.so.7.0 python2.7
> Python 2.7.2 (default, Mar 16 2012, 06:30:10)
> [GCC 4.2.1 20070719 ] on openbsd5
> Type "help", "copyright", "credits" or "license" for more information.
> >>> import ctypes
> >>> ctypes.cdll.LoadLibrary("libGLU.so")
> <CDLL 'libGLU.so', handle 20ec934f8 at 201f50790>
> ---8<---
>
> So, why the undefined symbol errors? Any ideas?
>
> --
> Best Regards
> Edd Barrett
>
> http://www.theunixzoo.co.uk
>
Hi,
I think you want RTLD_GLOBAL flag, by default RTDL_LOCAL is used.
>>> ctypes.CDLL("libGL.so", ctypes.RTLD_GLOBAL)
<CDLL 'libGL.so', handle 201136080 at 20c6454d0>
>>> ctypes.CDLL("libGLU.so", ctypes.RTLD_GLOBAL)
<CDLL 'libGLU.so', handle 209051308 at 20c645dd0>
