Re: Header problem with OGL on Cygwin

[Andre Bleau <bleau at igb dot umontreal dot ca>]

Paul M Sargent <Pauls at 3dlabs dot com> wrote:


> Hi All,
>
> I'm currently having some problems linking with OpenGL under cygwin. I was
> hoping somebody who understands the system might be able to offer some
> advice.
>
> The problem I'm having is that when I try to link my object files together
> with "-lglut32 -lglu32 -lopengl32" I get messages stating that there are
> "undefined reference"(s) to "_glBegin", amonst other symbols.
>
> Searching through the archives I've spotted a message stating that this
> means I'm compiling with the wrong headers (The symbols should be of the
> form _glBegin at 4'). It's at this point that I've lost the thread. My code
> contains "#include <GL/glut.h>" and doing a 'find / -name glut.h' only shows
> the one file located in /usr/include/GL.  Similarly doing the same find for
> gl.h gives me one in /usr/include/GL and one in /usr/include/w32api/GL.
>
> My compile command is "gcc -c <source file>"
> My link    command is "gcc -o <exe name> <object files> -lglut32 -lglu32
> -lopengl32"
>
> Am I missing something simple?
>
> Thanks for any help you can provide
>
> Paul

Paul,

In the past, 99% of the time such problem occured, people were _not_ 
linking with arguments in the appropriate order.

-lglut32 -lglu32 -lopengl32

must come after all objects on the command line.

Please try compiling and linking this test program; copy the following 
lines to helloGlut.c :

/*-------------------------- helloGlut.c start ----------------------------*/
#include <GL/glut.h>

void display_func()
{
glClear(GL_COLOR_BUFFER_BIT);
}

int main()
{
glutCreateWindow("Hello GLUT!");
glutDisplayFunc(display_func);
glutMainLoop();
return 0;
}
/*-------------------------- helloGlut.c end------------------------------*/

And compile and link with _the exact_ following lines:
gcc -c helloGlut.c
gcc -o helloGlut helloGlut.o -lglut32 -lglu32 -lopengl32

If you get any error messages, report them here verbatim and we'll work 
from there. Also send the ouput of "cygcheck -c" to a file and attach it to 
your email.



André Bleau, Cygwin's OpenGL package maintainer.

email: bleau at igb dot umontreal dot ca
(Fight SPAM: encode your email-address)

Please address all questions and problem reports about Cygwin's OpenGL 
package to cygwin at cygwin dot com .  


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