>> I removed *all* #includes (including math.h) except this one (note also the upper case 'H'):
>> #include <FL/glut.H>
>> and it works with FLTK 1.1 and FLTK 1.3 on Windows and Linux.>
> [..]
> "You must include FLTK's <FL/gl.h> header file. It will include the

	Thanks, this helped a lot.

	Yes, seems including those two is all that's needed to build 1.1 and 1.3.
	It seems too the crashes I was having that caused me to add those
	1.1 vs. 1.3 #ifdef's were related to my linker flags, and not the #include's.

	So now I can go back to the simple include header:

#include <FL/Fl.H>
#include <FL/Fl_Window.H>
#include <FL/glut.H>
#include <FL/gl.h>

	I kept the includes for Fl.H and Fl_Window.H since the example uses
	Fl_Window and Fl::run().

	I'm not sure what the #include <windows.h> was for.. must have been
	some left over windows-specific code I had from earlier iterations
	of writing the example.

>> BTW.: perhaps you could add linker commands (like mine above) to
>> your cheat page. At least I didn't find one for this example.

	I've changed it so that the compile/link instructions are in
	bold red so that it's easier to see.

	I should probably add this example to the examples dir in 1.3.

	Still, I'm not sure any of this helps the OP, who is on FLTK2.
	If I have time, given the above, I'll maybe try a port again.