opengl - Why glutWireCube() does not display my wire cube? -

i novice opengl , read glutwirecubedraws wire cube. not appearing on when run code, wondering do? draw cube or have gone wrong in code?

  #include<gl/glut.h>   gldouble cubesize= 10.0;   //functions declarations - prototypes   void init(void);   void display(void);   int main(int argc, char ** argv){  glutinit(&argc,argv);  glutinitdisplaymode(glut_single |glut_rgba);  glutinitwindowposition(100,100);  glutinitwindowsize(500,500);  glutcreatewindow("wire cube");  init();  glutdisplayfunc(display);   glutmainloop();  }  //functions implementaion - definition  void init(void){      glclearcolor(0.0,0.0,1.0,0.0);      glclear(gl_color_buffer_bit);      }  void display(void){      glbegin(gl_polygon);      glutwirecube(5.0);      glend();      glflush();      } 

calling glutwirecube not allowed inside glbegin/glend block. glvertex specify vertices , functions set current values of vertex attributes (like glnormal, glcolor, ...) can used there.

how glutwirecube internally works not specified. might use immediate mode, in case, own glbegin/glend calls.

conceptually, trying put cube gl_polygon not going work. gl_polygon drawing single, flat, convex polygon, , totally impossible draw whole cube 1 polygon.

furthermore, not set of gl_modelview or gl_projection matrices. means directly draw in clip space, , glutwirecube size 5 draw cube lies outside of viewing frustum, see nothing.