// declare base_func; no mark -> load-time imported symbol
void base_func(void);

// declare base_func; mark it as an exported symbol
__attribute__ ((visibility ("default"))) void plugin_func(void);

// define plugin_func
#include <stdio.h>
__attribute__ ((visibility ("default"))) void
plugin_func(void){
  printf("provided by plugin: {\n");
  printf(" ");
  base_func();
  printf(" ");
  base_func();
  printf("}\n");
}