Indirect OpenGL acceleration - New notes

Alexander Gottwald
Mon Mar 1 09:31:00 GMT 2004

On Sun, 29 Feb 2004, Harold L Hunt II wrote:

> That should result in a compilation of the currently empty 
> GL/windows/indirect.c file, which will cause XWin.exe to fail to link 
> since it can't find the OpenGL functions.  I am a little confused about 
> why XWin.exe fails to link on so many functions, since it seems that 
> -lopengl32 is providing those functions (look some of them up via 'nm -g 
> /usr/lib/w32api/opengl32.a | grep function_name')... I could use a few 
> pointers on what is happening there.

the opengl32.dll implements an rather old OpenGL API (1.2 afair).  But most 
vendors ship an opengl32.dll with their drivers which also implements the 
newer API.  But those functions must be linked dynamicly.

Another problem is the __stdcall issue. The windows dlls export symbols 
as _glBitmap@28 but normal GL headers define it as _glBitmap. This is 
due to the __stdcall call semantics.

So all OpenGL definitions in GL/gl.h must be wrapped with the APIENTRY macros.
OpenGL already has a GLAPI macros which simply must include the APIENTRY 

--           ICQ: 126018723
 Chemnitzer Linux-Tag 2004 - 6. und 7. März 2004

More information about the Cygwin-xfree mailing list