   Error of "GL_HISTOGRAM was not declared?
  My OpenGL program at Windows platform does include <gl.h> and <glext.h>, but it comes with an error of "GL_HISTOGRAM was not declared"? Is is correct? Or some other headers should include to avoid this issue? Tks.   
  Try using GLEW, it should manage to define that.Cheers,Gzaloprgm   ;  It's declared in the official glext.hhttp://www.opengl.org/registry/api/glext.h;  Thanks.  I included as below :==========================================================#define GLUT_DISABLE_ATEXIT_HACK#include "glew/glew.h"//#include "gl/gltools.h" #include "gl/math3d.cpp"#include "gl/glut.h"#include "gl/torus.c"#include "gl/vectormath.c"#include "gl/glext.h"#include "gl/gltools.cpp"#include <stdio.h>#include <stdlib.h>=========================================================The error was changed to "undefined reference to '_imp___glewHistogram'.  Any suggestion to fix it?  Tks.   ;  Thanks.  I included as below :==========================================================#define GLUT_DISABLE_ATEXIT_HACK#include "glew/glew.h"//#include "gl/gltools.h" #include "gl/math3d.cpp"#include "gl/glut.h"#include "gl/torus.c"#include "gl/vectormath.c"#include "gl/glext.h"#include "gl/gltools.cpp"#include <stdio.h>#include <stdlib.h>=========================================================The error was changed to "undefined reference to '_imp___glewHistogram'.  Any suggestion to fix it?  Tks.   ;  Sounds like a linker issue. I suggest that you link with the dynamic librray glew32.lib instead of the static library glew32s.lib   