c - Compilation errors when using GTK2+ with OpenGL? -

i writing c program makes use of fixed pipeline opengl , freeglut. however, use complete toolkit gtk+ instead of freeglut. cannot use gtk3+ not compatible old opengl code, use gtk2+.

i found this link example program called simple.c:

#include <math.h> #include <gtk/gtk.h> #include <gl/gl.h> #include <gtkgl/gtkglarea.h>  int init (gtkwidget *widget) { if (gtk_gl_area_make_current (gtk_gl_area(widget)))   {   glviewport(0,0, widget->allocation.width, widget->allocation.height);   glmatrixmode(gl_projection);   glloadidentity();   glortho(0,100, 100,0, -1,1);   glmatrixmode(gl_modelview);   glloadidentity();   }  return true; }  int draw (gtkwidget *widget, gdkeventexpose *event) { if (event->count > 0) return true;  if (gtk_gl_area_make_current (gtk_gl_area(widget)))   {   glclearcolor(0,0,0,1);   glclear(gl_color_buffer_bit);   glcolor3f(1,1,1);   glbegin(gl_triangles);   glvertex2f(10,10);   glvertex2f(10,90);   glvertex2f(90,90);   glend();   gtk_gl_area_swap_buffers (gtk_gl_area(widget));   }  return true; }  int reshape (gtkwidget *widget, gdkeventconfigure *event) { if (gtk_gl_area_make_current (gtk_gl_area(widget)))   glviewport(0,0, widget->allocation.width, widget->allocation.height);  return true; }  int main (int argc, char **argv) { gtkwidget *window, *glarea;  int attrlist[] = { gdk_gl_rgba, gdk_gl_red_size,1, gdk_gl_green_size,1, gdk_gl_blue_size,1, gdk_gl_doublebuffer, gdk_gl_none };  gtk_init (&argc, &argv); if (gdk_gl_query () == false) return 0;  window = gtk_window_new (gtk_window_toplevel); gtk_window_set_title (gtk_window(window), "simple"); gtk_container_set_border_width (gtk_container(window), 10); g_signal_connect (window, "delete_event", g_callback (gtk_main_quit), null);  /* should delete gtk_gl_area widgets before exit or else    glx contexts left undeleted, may cause problems (=core dump)    in systems.    destroy method of objects not automatically called on exit.    need manually enable feature. gtk_quit_add_destroy()    top level windows unless    destroy signal other means. */  gtk_quit_add_destroy (1, gtk_object(window));  glarea = gtk_widget(gtk_gl_area_new (attrlist)); gtk_widget_set_size_request (gtk_widget(glarea), 100, 100);  gtk_widget_set_events (gtk_widget(glarea), gdk_exposure_mask | gdk_button_press_mask);  g_signal_connect (glarea, "expose_event", g_callback(draw), null); g_signal_connect (glarea, "configure_event", g_callback(reshape), null); g_signal_connect (glarea, "realize", g_callback(init), null);  gtk_container_add (gtk_container(window), gtk_widget(glarea)); gtk_widget_show (gtk_widget(glarea)); gtk_widget_show (gtk_widget(window));  gtk_main (); return 0; } 

but unfortunately requeries file don't know get, gtk_opengl.h

i unsuccessfully tried compile simple.c code

gcc simple.c -o helloworld `pkg-config --libs gtk+-2.0` 

and, of course, got following error:

fatal error: gtk_opengl.h: no such file or directory 

any ideas on how make simple.c compile? or on how combine opengl gtk2+?

on debian stable box had install libgtkgl2.0-dev , add --cflags & gtkgl-2.0 pkg-config invocation:

gcc simple.c -o helloworld `pkg-config --cflags --libs gtk+-2.0 gtkgl-2.0`