[HOpenGL] -O strangeness

Wolfgang Thaller wolfgang.thaller@gmx.net
Thu, 7 Mar 2002 17:21:24 +0100


>[...] appears to scale the line by 2, [...]


>When compiling Lines.hs with -O, I get
>
>/tmp/ghc14725.hc: In function `s8Wy_ret':
>/tmp/ghc14725.hc:474: warning: implicit declaration of function `glScalef'

Compilation with -O makes GHC compile via the C compiler. GHC should 
have been told
to #include <GL/gl.h> in that case, but at least for Lines.hs, it 
didn't do so properly.
Make sure that an option like '-#include <GL/gl.h>' (glu.h or glut.h 
should be fine, too)
gets passed to the compiler or that there is an {-# OPTIONS -#include 
... #-} line at the
top of that file.
If the C compiler calls a function that expects a float argument 
without having the proper
declaration, it passes a double instead, which is Not Good(tm).

Not exactly a solution, but it should explain the problem...


Wolfgang