Super Function in C

super.c

// This isn't exactly like having super-methods, especially since there are no
// classes or inheritances in C, but this can be useful with things like LD_PRELOAD
// where you want to override or proxy an existing function, and want the function
// to continue executing as it usually would(vs being a no-op).

#define _GNU_SOURCE
#include <dlfcn.h>

void glVertex3f(float x, float y, float z){  // an OpenGL function
  static void (*super)(float, float, float) = NULL;
  if (!super)
    super = (void(*)(float, float, float)) dlsym(RTLD_NEXT, "glVertex3f");
  super(x, y, z);
}